CN114990505B - Gallium oxide film based on optical waveguide effect and preparation method thereof - Google Patents
Gallium oxide film based on optical waveguide effect and preparation method thereof Download PDFInfo
- Publication number
- CN114990505B CN114990505B CN202210366065.2A CN202210366065A CN114990505B CN 114990505 B CN114990505 B CN 114990505B CN 202210366065 A CN202210366065 A CN 202210366065A CN 114990505 B CN114990505 B CN 114990505B
- Authority
- CN
- China
- Prior art keywords
- gallium oxide
- sputtering
- oxide film
- film
- temperature
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
- C23C14/34—Sputtering
- C23C14/35—Sputtering by application of a magnetic field, e.g. magnetron sputtering
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y20/00—Nanooptics, e.g. quantum optics or photonic crystals
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y40/00—Manufacture or treatment of nanostructures
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/0021—Reactive sputtering or evaporation
- C23C14/0036—Reactive sputtering
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/06—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the coating material
- C23C14/08—Oxides
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/58—After-treatment
- C23C14/5806—Thermal treatment
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/44—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the coatings, e.g. passivation layer or anti-reflective coating
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Abstract
The invention provides a gallium oxide film based on an optical waveguide effect and a preparation method thereof. The method comprises the following steps: firstly, adopting a radio frequency mode of magnetron sputtering, keeping background vacuum, working pressure, sputtering power, duration and atmosphere technological parameters as specific values, setting the optimal sputtering temperature by utilizing the strong dependency relationship between the film structure and the sputtering temperature, and sputtering to prepare the gallium oxide film with the obvious nano-pillar structure on the section.
Description
Technical Field
The invention belongs to the technical field of semiconductors, and particularly relates to a gallium oxide film based on an optical waveguide effect and a preparation method thereof.
Background
Gallium oxide (Ga) 2 O 3 ) Very extensive discussion and research is underway due to the ultra-large forbidden band width (4.9 eV), high chemical and physical stability. Ga 2 O 3 The absorption wavelength is 253nm, and the light transmittance is good in the visible light band, so Ga is applied 2 O 3 The film is used as a high-light-transmission passivation layer of the top layer of the light-emitting diode, and has outstanding industrialization potential.
Preparation of high quality Ga 2 O 3 The thin film can be mainly prepared by Chemical Vapor Deposition (CVD), laser pulse deposition (PLD), molecular Beam Epitaxy (MBE), metal organic chemical vapor epitaxy (MOCVD), magnetron Sputtering (MS) and other methods. In different preparation methods of the deposited oxide film, the magnetron sputtering technology is mature, has high speed, low cost and no pollution, is suitable for large-area film formation preparation, and is one of the preferred methods in the industrial process. Sputter deposited Ga 2 O 3 The film is amorphous, and the core thought of the prior art is as follows: after sputtering, the annealing process is needed to find out the preferable annealing temperature, annealing time and annealing atmosphere, so as to convert the amorphous gallium oxide film into single crystal beta-Ga to the maximum extent 2 O 3 A film to increase its transmittance. The transformation from amorphous to single crystal generally requires high temperatures of 800-1100 c and the time required for the anneal to maintain the high temperature is generally 60 to 90 minutes. The high temperature favors the transformation of gallium oxide from amorphous to monocrystalline, but another concurrent change in contradiction is: the high temperature for a long time causes oxygen atoms in gallium oxide to be lost, so that oxygen vacancies in the film are increased, and the optical transmittance of the corresponding film is reduced.
Disclosure of Invention
The invention aims to overcome the defects of the prior art, and provides a gallium oxide film based on an optical waveguide effect and a preparation method thereof, so as to solve the problem that the optical transmittance of the film is easy to be reduced due to long-time high temperature in the preparation process of the gallium oxide film in the prior art. The invention is based on a radio frequency magnetron sputtering system, utilizes a nano-pillar structure stacked in the film forming process of a gallium oxide film under the temperature modulation effect, and generates an optical waveguide effect on incident light of long-wave, medium-wave ultraviolet rays (uv-a, uv-b) and blue light wave bands, thereby obtaining higher light transmittance. After the sputtering preparation, the gallium oxide nano-pillar optical waveguide structure is solidified and optimized by matching with the adjustment of the rapid thermal annealing process parameters, so that the aim of further improving the light transmittance is fulfilled.
In order to achieve the purpose, the invention is realized by adopting the following technical scheme:
the preparation method of the gallium oxide film based on the optical waveguide effect is characterized by comprising the following steps of:
step 1, preparing a gallium oxide process film on a substrate by a magnetron sputtering method, wherein the sputtering temperature in the magnetron sputtering process is 200-400 ℃; the mixed gas of argon and oxygen is used as working atmosphere in the sputtering process;
step 2, annealing the prepared gallium oxide process film at 100-200 ℃ for 2-30 s under the condition of nitrogen and nitrous oxide mixed gas, and obtaining the gallium oxide film after annealing; the gallium oxide film consists of two-dimensional arrayed nano columns.
The invention further improves that:
preferably, in the step 1, the substrate is sequentially subjected to ultrasonic cleaning by water, acetone, water, absolute ethyl alcohol and water before magnetron sputtering; the substrate is a double-polished (0001) plane sapphire substrate.
Preferably, in step 1, the magnetron sputtering temperature is 350 ℃.
Preferably, in the step 1, the working pressure of the magnetron sputtering is 0.8Pa, and the sputtering time is 20min; the power of the magnetron sputtering is 200W.
Preferably, in the step 1, the sputtering working atmosphere has an oxygen content of 2.5% by volume and the balance of argon.
Preferably, the annealing temperature is 140 ℃, and the annealing time is 3-5 s.
Preferably, in the step 2, the volume ratio of nitrogen in the annealing atmosphere is 95%, and the volume ratio of nitrous oxide is 5%.
The gallium oxide film based on the optical waveguide effect, which is prepared by any one of the preparation methods, consists of two-dimensionally arranged nano-pillars, and the length direction of the nano-pillars is perpendicular to the two-dimensionally arranged plane.
Preferably, the thickness of the gallium oxide film is 237-257 nm.
Preferably, the gallium oxide film has an average light transmittance of > 97% in the blue light band range of 400nm to 500 nm.
Compared with the prior art, the invention has the following beneficial effects:
the invention provides a preparation method of a gallium oxide film based on an optical waveguide effect, which is a method for improving the transmissivity of the gallium oxide film in a specific incident light frequency band by limiting the form of crystals in the film. The method comprises the following steps: firstly, adopting a radio frequency mode of magnetron sputtering, keeping background vacuum, working pressure, sputtering power, duration and atmosphere technological parameters as specific values, setting the optimal sputtering temperature by utilizing the strong dependency relationship between the film structure and the sputtering temperature, and sputtering to prepare the gallium oxide film with the obvious nano-pillar structure on the section. And step two, the annealing treatment step is carried out: and (3) carrying out rapid thermal annealing treatment on the prepared gallium oxide film with the section provided with the nano-pillar structure by using a rapid thermal treatment furnace, so that the nano-pillar structure is more compact and solidified, and the final high-light-transmittance gallium oxide film is obtained after annealing. The invention utilizes the nano-pillar structure before gallium oxide film formation, uses the temperature which is most beneficial to the growth of the nano-pillar structure to sputter, then adopts rapid thermal annealing to solidify and optimize the nano-pillar, promotes the optical waveguide effect of the nano-pillar cavity to specific incident light, and realizes the preparation of the gallium oxide film with high transmittance to the specific incident light. The process of the invention is simple and stable. The high transmission frequency band for incident light can be adjusted by changing annealing parameters (temperature, time and atmosphere), so that the flexibility is provided.
The invention does not take the generated monocrystal gallium oxide film as a means for improving the light transmittance, but innovatively utilizes the strong relation between the structural change of the gallium oxide film and the sputtering temperature in the radio frequency sputtering process, and based on the specific sputtering temperature, the light waveguide effect is generated by the 'nano column' structure formed by longitudinally stacking gallium oxide particles for the incident light of a specific wave band in the 'film forming' process of gallium oxide, so as to realize the purpose of enhancing the light transmittance of the incident light of the specific wave band. After sputtering, the rapid thermal annealing is purposefully combined, only a lower temperature of tens of seconds is required, instead of realizing the conversion from amorphous to single crystal, the gallium oxide nano-pillar structure generated by sputtering is solidified and optimized, so that the pillar structure is more compact, the optical waveguide effect in the pillar cavity is stronger, and the transmittance of incident light in a specific wave band is further improved.
The invention also discloses a gallium oxide film based on the optical waveguide effect, which consists of tightly combined columnar crystals, wherein the combination between the columns is compact, defects and dangling bonds in a column cavity are few, crystal grains are longitudinally stacked to form a compact column, and the gallium nitride film has high transmittance for a blue light wave band of 400-500 nm of an incident light wave band.
Drawings
FIG. 1 Ga at different sputtering temperatures 2 O 3 SEM cross-sectional morphology of the film (before rapid thermal annealing);
wherein, (a) is room temperature sputtering; (b) sputtering at 100deg.C; (c) sputtering at 200 ℃; (d) sputtering at 250 ℃; (e) sputtering at 300 ℃; (f) sputtering at 350 ℃; (g) FIG. 400℃sputtering; (h) drawing 500 ℃ sputtering; FIG. 600℃sputtering is shown.
FIG. 2 is a comparison of SEM cross-sectional morphology of columnar structures at two sputtering temperatures, before and after annealing;
wherein, (a) is a 250 ℃ sputter unannealed; (b) FIG. 250 ℃ sputtering and annealing; (c) FIG. 350 ℃ sputtering unannealed; (d) sputtering and annealing at 350 ℃;
FIG. 3Ga 2 O 3 A thin film section columnar growth change model analysis chart;
FIG. 4 model of film growth mechanism;
wherein (a) the figure shows a three-dimensional island growth pattern for deposition growth; (b) drawing of a two-dimensional layered growth pattern for deposition; (c) drawing a two-dimensional layered growth plus three-dimensional island growth pattern;
FIG. 5Ga 2 O 3 A thin film dielectric optical waveguide model diagram;
FIG. 6 is a diagram of the steps in the practice of the present invention;
FIG. 7 Ga in 400 nm-500 nm band at different sputtering temperatures 2 O 3 Film transmittance plot.
Detailed Description
The invention is described in further detail below with reference to the drawings and the specific embodiments.
Referring to fig. 6, the invention discloses a gallium oxide film based on optical waveguide effect and a preparation method thereof, wherein the preparation method specifically comprises the following steps:
step 1, in the sputtering stage, gallium oxide nano-pillars are generated by temperature control
And (3) a substrate cleaning process: and (3) sequentially carrying out ultrasonic cleaning on the (0001) double-polished sapphire substrate in deionized water (10 min), acetone (15 min), deionized water (10 min), absolute ethyl alcohol (15 min) and deionized water (10 min) to remove various impurities on the surface of the sapphire substrate, and then purging the ultrasonically cleaned substrate by a nitrogen gun. Then, the cleaned sapphire substrate was placed on a substrate holder and rapidly placed into a sputtering chamber. Closing the chamber, and evacuating the background of the sputtering chamber to a temperature below 4.0X10 -4 After Pa, introducing working gas: high purity (99.999%) Ar 2 (flow rate 39 sccm) and O 2 (flow rate 1 sccm), i.e., oxygen content by volume was 2.5%.
The working pressure during sputtering was set to 0.8Pa and the sputtering period was 20 minutes. Sputtering adopts a radio frequency mode, and the power is 200W. The sputtering temperature (substrate temperature) is set to 200 to 400 ℃, and the most preferable sputtering temperature is 350 ℃. Before formal sputtering, a heating program is opened to raise the temperature to a corresponding sputtering temperature value, and a target shielding plate is closed to perform pre-sputtering to remove Ga 2 O 3 Contamination impurities on the surface of the ceramic target. Preparing Ga with most obvious nano-pillar structure on film section at optimal sputtering temperature 2 O 3 Film, film thickness256nm.
The temperature of 350 ℃ which is the temperature of the film with the most obvious nano-pillar structure in the section is determined by the following three steps:
the sputtering temperatures (substrate temperatures) in the first step were set to Room Temperature (RT), 100 ℃, 150 ℃, 200 ℃, 250 ℃, 300 ℃, 350 ℃, 400 ℃, 450 ℃, 500 ℃, 550 ℃ and 600 ℃ in total, respectively, for 12 temperature cases.
(second step) film thickness was measured, and it was concluded that under this sputtering condition (only the sputtering temperature was changed), the effect of temperature differences on the resulting film thickness was small, and that at 12 sputtering temperatures, the film thickness was 247 (±10) nm.
And (3) carrying out Scanning Electron Microscope (SEM) test analysis on the prepared film to observe the surface morphology and the cross-sectional morphology of the film.
Ga at different sputtering temperatures without rapid thermal annealing 2 O 3 A graph of the cross-sectional (side) topography change of the film is shown in fig. 1.
After a rapid thermal anneal at 140 ℃ for 4 seconds, SEM cross-sectional morphology pairs of columnar structures at two temperatures, which vary before and after annealing, are shown in four graphs such as those shown in fig. 2. The film cross-sectional structure changes with increasing sputtering temperature, which shows four-stage changes, as shown in FIG. 3Ga 2 O 3 And the film section columnar growth change model diagram is shown.
Stage one: amorphous, grain random packing; →
Stage two: a loose columnar structure; →
Stage three: a dense columnar structure; →
Stage four: a continuous film structure.
In FIG. 1, ga prepared by sputtering at room temperature 2 O 3 The film is amorphous, and in the first of the four stages, particles are deposited unordered to each other, without crystallization and with many defects. The sputter temperature increases to 100 ℃ and 150 ℃ also belong to stage one, as shown in the following figures (a) and (b).
Referring to fig. 1, when the sputtering temperature is increased to 20At 0 ℃, it can be clearly observed that Ga 2 O 3 The film evolves from irregular accumulation of particles at low temperature into large clusters and particles which are accumulated longitudinally to form a more obvious columnar structure, namely: gallium oxide nano-pillars appear, and the process proceeds to stage two of the four stages. At 200 ℃, the column diameter is thicker, more cluster particles are in the column, the boundaries among the particles are clear, the arrangement is loose, and the whole in the column is disordered. And the gaps between the columnar structures are wider, and the arrangement between the columns is not tight. The sputtering temperature was raised to 250 ℃. The inner and outer of the nano-pillar structure is still loose, and still is classified as stage two.
Referring to fig. 1 (e) and (f), the gallium oxide nano-pillar structure is denser, the pillar diameter is reduced, large particle clusters in the pillar are fused, the state of separation between particles tends to be insignificant, and the arrangement of grains in the pillar tends to be tighter when the sputtering temperature is increased to 300 ℃ as compared with the pillar structure at 200 ℃ and 250 ℃. The column-column space is also reduced, the column-column arrangement is also denser, and the phase two enters the phase three. As the temperature increases to 350 c again, the gallium oxide nano-pillar structure is more obvious and more compact at this time, and the pillar diameter is further reduced (the pillar diameter is about ten nanometers order of magnitude) and the arrangement of grains in the pillar cavity tends to be more compact than that of the pillar structure at 300 c. The column-column spacing is further reduced and the column-column arrangement is the most dense, which is the column-optimum stage of stage three. Further, the diameter of the column is in the range of 10 to 20nm.
Referring to fig. 1 (g), fig. h and fig. i), when the temperature is raised to 400 ℃, the originally apparent columnar structure starts to disappear, and the "film formation" stage starts to be entered. This is because the temperature is further raised, the mobility of sputtered atoms on the surface of the sapphire substrate is increased, the gaps between the inside and outside of the columnar structure are reduced to disappear, grains start to aggregate into a continuous film structure, and the stage four starts to be entered. The continuous film structure was progressively more distinct and denser as the temperature was increased from 400 ℃ through 450 ℃, 500 ℃, 550 ℃ to 600 ℃. The sharp small grains and grain boundaries therebetween are seen in the film, and the degree of transformation from polycrystalline to single crystal in the film increases, continuing to remain in stage four.
Fig. 3 shows a four-stage change in the corresponding film cross-sectional structure: the corresponding sectional view is drawn by amorphous and crystal grain random stacking, loose columnar structure, compact columnar structure and continuous film structure. The first region corresponds to Ga deposited at a sputtering temperature of room temperature 2 O 3 The film structure is irregularly piled up and has more holes, and the sputtering temperature is corresponding to the room temperature to 150 ℃. And the second region corresponds to a film structure at the sputtering temperature of 200 ℃ and 250 ℃, and clusters and particles are longitudinally stacked to form coarse and sparse columns. Region three represents the dense columnar structure formed when the sputtering temperature reached 300 ℃ and 350 ℃. The continuous film structure exhibited at the sputtering temperature of 400 ℃, 450 ℃, 500 ℃, 550 ℃, 600 ℃ is the corresponding region four.
The model analysis chart of four stages of amorphous crystal grain random accumulation, loose columnar structure, compact columnar structure and continuous film structure, which are represented by the film cross-section morphology of the film represented by the figure 3, is consistent with the cross-section morphology transformation process obtained by SEM measurement corresponding to the figure 1.
The columnar structure of the gallium oxide film section at a specific sputtering temperature is explained by the film growth mechanism model diagram of fig. 4. Preparation of Ga by sputtering on sapphire substrate 2 O 3 The nucleation process of the film is mainly non-spontaneous nucleation, the phase change free energy of the formed atomic groups is the driving force of the film nucleation, and the change of the free energy of the phase change per unit volume, the critical nucleation free energy and the non-spontaneous nucleation barrier height can cause the growth mode to be three modes shown in fig. 4. FIG. 4 (a) shows a three-dimensional island-like growth mode (VW mode, volmer-Weber growth mode), wherein the larger the interaction energy between the grown particles is, the larger the potential barrier height of the non-spontaneous nucleation is, and the larger the critical nucleation free energy is. The barrier to be overcome by particle diffusion is high, so that the diffusion capability of particles on the surface of a substrate is weak, the particles are easy to aggregate into fractal islands, and the fractal islands continue to be increased to form island-shaped growth structures. At lower sputtering temperatures, ga also has a large number of nuclei competing for growth due to the limited ability of atoms to diffuse during deposition 2 O 3 The thin film is mainly deposited and grown in the three-dimensional island growth mode (VW mode) of fig. 4 (a), and the resulting thin film has many defects. Application of three-dimensional island growth mode to Ga 2 O 3 Stage one of film section change. Fig. 4 (b) shows a two-dimensional lamellar growth mode (FM mode, frank-van der Merwe growth mode) in which the barrier height for non-spontaneous nucleation is the lowest, the critical nucleation free energy is the smallest, and the nucleation rate is high. The entire substrate surface is covered with a first layer of material to be grown and a second layer is grown on the first layer, followed by a layer-by-layer coverage. When the sputtering temperature is increased to 400 ℃ or above, the columnar structure begins to disappear, a thin film structure with few holes begins to be gradually formed, and the stage four is entered. The sputtering temperature is increased, so that the diffusion speed of the deposited particles is increased, a compact island with larger size is easy to form, and the growth mode gradually tends to grow layer by layer from an island shape, namely, the film is mainly deposited in a two-dimensional lamellar growth mode (FM mode) in fig. 4 (b). Fig. 4 (c) is a two-dimensional lamellar growth plus three-dimensional island growth mode (SK mode, stranski-Krastanow growth mode) in which a change from lamellar growth to island growth, that is, a transition from two-dimensional growth to three-dimensional growth, occurs. The larger the size of critical cores to be formed is when the sputtering temperature is raised to 200 ℃ or higher (not to 400 ℃), the lower the critical free energy of nucleation is, and the potential barrier of non-spontaneous nucleation is not low, so that the deposited film first forms a coarse island-like structure at high temperature. And at the same time, the aggregation of adsorption particles and the increase of dislocation number in the film growth process cause the nano crystal grains to be longitudinally stacked to form columnar crystal forms. Thus, when the temperature is raised to 200 ℃ or higher (not to 400 ℃), a distinct columnar structure is formed. The columnar structure has lower density at grain boundaries and weaker bonding strength. Namely: the temperature rise changes the growth model from island growth to lamellar-island growth, ga 2 O 3 The film was deposited mainly in the two-dimensional layered growth plus three-dimensional island growth mode of fig. 4 (c) (SK mode), corresponding to Ga 2 O 3 Stage two and stage three of film section change. The invention is obtained through experimental verification: under this preparation condition, the sputtering temperature of 350 ℃ is the preferred temperature for generating the most dense nanopillars of stage three.
Step 2, rapid thermal annealing is carried out to solidify and optimize the gallium oxide nano-pillar structure
The purpose of rapid thermal annealing is not to convert to a single crystal film to the greatest extent at high temperatures for a long time, but rather to preserve and optimize the columnar structure so that the column-to-column is denser, the column inner diameter is finer, the grains within the column cavity are more fused with each other, and defects and dangling bonds within the column cavity are fewer.
The selection steps of the holding time length, the holding temperature and the annealing atmosphere of the rapid thermal annealing are also judged by the measurement of the cross section morphology of a Scanning Electron Microscope (SEM), the measurement of X-ray diffraction (XRD) and the measurement of the transmittance of a spectrophotometer. After the comparison and preference of the combination of different durations (the rapid thermal annealing holding time ranges from 2 seconds to 30 seconds) and temperatures (the rapid thermal annealing holding temperature ranges from 100 ℃ to 200 ℃), the temperature of the rapid thermal annealing furnace is set to 140 ℃ and the holding time is less than 5 seconds. The significance of the invention for selecting the low temperature and the extremely short annealing time is that: if the annealing temperature is further increased, if the annealing time is further prolonged to be in units of minutes, the gallium oxide molecules in the film are more energetic and more abundant, and the trend of ordered arrangement of crystal lattices of the single crystal is enhanced, namely, the proportion of the transformation trend from amorphous to single crystal is increased. The annealing temperature is not very high, and the annealing time is extremely short, so that gallium oxide molecules only obtain limited energy and move for a shorter distance. The result of the short distance movement is that the existing columnar structure still exists, but the grains in the columnar cavity are orderly arranged, the columnar diameter is smaller, the column spacing is smaller, and the change of single crystal membranization and column disappearance is not needed. For setting of the atmosphere of rapid thermal annealing, the invention compares: (a) vacuum; (b) high purity argon (99.999% or more); (c) high purity oxygen (99.999% or more); (d) After the mixed gas of high-purity nitrogen and high-purity oxygen, (e) the mixed gas of high-purity nitrogen and high-purity hydrogen, and (f) the mixed gas of high-purity nitrogen and high-purity nitrous oxide, and the results of the transmittance measurement of a Scanning Electron Microscope (SEM), X-ray diffraction (XRD) and a spectrophotometer are combined, the mixed gas of high-purity nitrogen and high-purity nitrous oxide is determined to be the optimal rapid thermal annealing atmosphere, wherein the volume ratio of the high-purity nitrogen is 95%, and the volume ratio of the high-purity nitrous oxide is 5%. Nitrogen acts as a protective gas, while nitrous oxide gas acts primarily in annealing: the "N-O" bond of the nitrous oxide molecule is a single bond, the bond energy being relatively small (bond energy 201kJ/mol at one standard atmosphere). The "o=o" bond of an oxygen molecule is a double bond, and the bond energy (498 kJ/mol bond energy at one standard atmosphere) is about 2.5 times that of the "N-O" bond. At the same atmospheric pressure (the rapid thermal annealing process is always kept at a standard atmospheric pressure), and also at a temperature in the range of 100 ℃ to 200 ℃, oxygen atoms are more likely to be decomposed from nitrous oxide molecules than oxygen atoms are decomposed from oxygen molecules. More free oxygen atoms that are decomposed more effectively supplement oxygen vacancies caused by oxygen atoms overflowing from the gallium oxide film at this less high temperature range.
The invention finally determines the optimal parameters of the rapid thermal annealing as follows: the temperature is 140 ℃, the holding time is less than 5 seconds, and the annealing atmosphere is the mixture of high-purity nitrogen (the purity is more than or equal to 99.999 percent and the volume ratio is 95 percent) and high-purity nitrous oxide (the purity is more than or equal to 99.999 percent and the volume ratio is 5 percent). Under this annealing condition, high transmittance will result for incident blue light (400 nm to 450 nm). The micro-adjustment of the annealing parameters brings about a micro-variation of the diameter of the nanopillar (slightly increasing the annealing time for several seconds causes a relatively large variation of slightly changing the inner diameter of the nanopillar, whereas, slightly decreasing the annealing time for several seconds causes a relatively small variation of the inner diameter of the nanopillar) so that the incident light in the ultraviolet and mid-ultraviolet ranges also obtains better transmittance.
5.3 optical waveguide model of gallium oxide thin film section nano column
The propagation path of incident light in the column cavity for multiple refraction is represented by the optical waveguide model in FIG. 5, and in the film sputtering preparation stage, when the film cross-section structure is stage three, ga 2 O 3 The crystallization quality of the film is improved, the inner diameter of the column and the gap between the column and the column edge of the nano columnar structure with the film section are minimum, crystal grains are longitudinally piled up to form a compact column, the refractive index in the column cavity is higher than that of the column edge, and the propagation path of incident light in the column cavity for multiple refraction is represented by the optical waveguide model in figure 5. At 350 ℃, the column structure is the most compact, the column diameter is the thinnest, and the light transmittance of the column tail output end caused by multiple refraction and convergence in the column cavity is the optimal. While at the level ofAnd the second section has loose column structure and large column diameter, and light transmittance of the column tail output end caused by multiple refraction and convergence in the column cavity is inferior. On entering stage four, the pillar structure tends to disappear and turn into a film, and the optical waveguide disappears.
The thin film is subjected to rapid thermal annealing after being sputtered at 350 ℃, the diameter of the nano column is thinner than that of the thin film before annealing, the columnar structure is more compact, the light transmittance of the column tail output end caused by more refraction and convergence in the column cavity is better, and the optical waveguide effect is more remarkable in improvement of the projection rate.
FIG. 7 shows the incident light wavelength band of 400nm to 500nm, ga, after the process based on the same rapid thermal annealing parameters, at different sputtering temperatures 2 O 3 Film transmittance versus graph. Ga prepared 2 O 3 The average light transmittance of the film in the blue light wave band range of 400 nm-500 nm is more than 97%, and the film belongs to the oxide film with high light transmittance. From fig. 7, it is observed that: the light transmittance of the film is improved when the columnar structure exists, the light transmittance of the compact columnar structure is superior to that of the loose columnar structure, and the light transmittance of the loose columnar structure is better than that of the film structure. Ga at a sputtering temperature of 350 DEG C 2 O 3 The crystallization quality of the film is improved, the column diameter and the edge clearance of the columnar structure are reduced, crystal grains are stacked into compact columns, the columnar structure is most obvious, and the column cavity wall structure is also most compact. The refractive index of the inner wall of the column cavity is higher than that of the column edge and higher than that between the columns. So that the incident light of the blue light wave band is coupled into the gallium oxide column cavity, and the total emission occurs in the column cavity, namely: the column cavities constitute an effective cylindrical optical waveguide structure. The propagation path of incident light from the surface of the thin film on one side, along the inner diameter of the columnar structure, and carrying out multiple refraction on the inner wall of the columnar cavity is represented by the optical waveguide model of fig. 5. At 350 ℃, the column structure is the most compact, the column cavity inner wall structure is the most compact, and the column cavity inner wall refractive index is the highest. The diameter of the column is smaller, and the most times the light is refracted along the columnar optical waveguide. The light transmittance of the output end of the post tail caused by the convergence of the high refractive index and more refractive times is optimal. At 250 ℃, the column structure is loose, the column cavity inner wall structure is also loose, and the refractive index of the column cavity inner wall is lower than that at 350 ℃. The columnar diameter is increased, and the number of times of refraction of light along the columnar optical waveguide is also higher than that at 350 DEG CAnd (3) reducing. The lower refractive index and the reduced number of refractive times reduce the light transmittance at the output end of the post tail caused by the convergence of the incident light in the post cavity. At 400 ℃ and above, the pillar structure tends to disappear and turn into a film, and the optical waveguide disappears.
The properties of gallium oxide thin films are largely dependent on their structure. The invention is based on a radio frequency magnetron sputtering method, and utilizes the strong relation between the gallium oxide film structure and the sputtering temperature to purposefully control the temperature so that the gallium oxide film generates a special optical waveguide structure. The light waveguide structure is optimized by combining the effective control of atmosphere, temperature and time in the subsequent rapid thermal annealing process, so that the effect of further improving the transmissivity of the gallium oxide in the incident light (long wave, medium wave ultraviolet and blue light wave bands) of a specific frequency band is realized, and the gallium oxide is Ga 2 O 3 The film provides an innovative method as a high-light-transmission passivation layer of the LED with a specific wave band.
Example 1
And (3) a substrate cleaning process: and (3) sequentially carrying out ultrasonic cleaning on the (0001) double-polished sapphire substrate in deionized water (10 min), acetone (15 min), deionized water (10 min), absolute ethyl alcohol (15 min) and deionized water (10 min) to remove various impurities on the surface of the sapphire substrate, and then purging the ultrasonically cleaned substrate by a nitrogen gun. Then, the cleaned sapphire substrate was placed on a substrate holder and rapidly placed into a sputtering chamber. Closing the chamber, vacuumizing the background of the sputtering chamber to be lower than 4.0x10 < -4 > Pa, and introducing working gas: high purity (99.999%) Ar 2 (flow rate 39 sccm) and O 2 (flow rate 1 sccm), i.e., oxygen content by volume was 2.5%.
The working pressure during sputtering was set to 0.8Pa and the sputtering period was 20 minutes. Sputtering adopts a radio frequency mode, and the power is 200W. The sputtering temperature (substrate temperature) was set at 350 ℃, and a gallium oxide process film was obtained after magnetron sputtering.
And (3) annealing the gallium oxide process film, wherein the atmosphere in the annealing process is 95% of high-purity nitrogen, 5% of high-purity nitrous oxide, the annealing temperature is 140 ℃, and the annealing time is less than 4s. The thickness of the prepared film was about 247nm.
Example 2
The sputtering temperature (substrate temperature) of this example was set to 200℃with respect to example 1, and the thickness of the prepared film was about 249nm.
Example 3
The sputtering temperature (substrate temperature) of this example was set to 250℃with respect to example 1, and the thickness of the prepared film was about 250nm.
Example 4
The sputtering temperature (substrate temperature) of this example was set to 300℃with respect to example 1, and the thickness of the prepared film was about 255nm.
Example 5
The sputtering temperature (substrate temperature) of this example was set to 400℃with respect to example 1, and the thickness of the prepared film was about 257nm.
Example 6
The annealing temperature was 100℃and the annealing time was 5s in this example, relative to example 1, to prepare a film having a thickness of about 253nm.
Example 7
The annealing temperature was 120℃and the annealing time was 5s in this example compared to example 1, and the thickness of the prepared film was about 240nm.
Example 8
The annealing temperature was 150℃and the annealing time was 5s in this example compared to example 1, and a film thickness of about 238nm was produced.
Example 9
The annealing temperature was 160℃and the annealing time was 5s for example 1, and a film thickness of about 237nm was produced.
Example 10
The annealing temperature was 180℃and the annealing time was 5s in this example compared to example 1, and a film thickness of about 245nm was produced.
Example 11
The annealing temperature was 200℃and the annealing time was 5s in this example compared to example 1, and a film thickness of about 237nm was produced.
Example 12
The annealing temperature was 160℃and the annealing time was 5s in this example compared to example 1, and a film thickness of about 245nm was produced.
Example 13
The annealing temperature was 180℃and the annealing time was 5s in this example, relative to example 1, to prepare a film having a thickness of about 247nm.
Example 14
The annealing temperature was 200℃and the annealing time was 5s in this example compared to example 1, and a film thickness of about 242nm was produced.
Example 15
The annealing time was 5s with respect to example 1.
Example 16
The annealing time was 8s with respect to example 1.
Example 17
The annealing time was 10s with respect to example 1.
Example 18
The annealing time was 15s with respect to example 1.
Example 19
The annealing time was 20s relative to example 1.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, alternatives, and improvements that fall within the spirit and scope of the invention.
Claims (9)
1. The preparation method of the gallium oxide film based on the optical waveguide effect is characterized by comprising the following steps of:
step 1, preparing a gallium oxide process film on a substrate by a magnetron sputtering method, wherein the sputtering temperature in the magnetron sputtering process is 200-400 ℃; the mixed gas of argon and oxygen is used as working atmosphere in the sputtering process; the working pressure of the magnetron sputtering is 0.8Pa, and the sputtering time is 20min; the power of the magnetron sputtering is 200W;
step 2, annealing the prepared gallium oxide process film at 100-200 ℃ for 2-30 s under the condition of nitrogen and nitrous oxide mixed gas, and obtaining the gallium oxide film after annealing; the gallium oxide film consists of two-dimensional arrayed nano columns.
2. The method for preparing a gallium oxide film based on an optical waveguide effect according to claim 1, wherein in step 1, the substrate is sequentially subjected to ultrasonic cleaning by water, acetone, water, anhydrous ethanol and water before magnetron sputtering; the substrate is a double-polished (0001) plane sapphire substrate.
3. The method for preparing a gallium oxide film according to claim 1, wherein in step 1, the magnetron sputtering temperature is 350 ℃.
4. The method for preparing a gallium oxide film according to claim 1, wherein in step 1, the sputtering atmosphere has an oxygen content of 2.5% by volume and the balance is argon.
5. The method for preparing a gallium oxide film based on an optical waveguide effect according to claim 1, wherein the annealing temperature is 140 ℃ and the annealing time is 3-5 s.
6. The method for producing a gallium oxide film according to claim 1, wherein in step 2, the volume ratio of nitrogen in the annealing atmosphere is 95% and the volume ratio of nitrous oxide is 5%.
7. A gallium oxide thin film based on an optical waveguide effect, produced by the production method according to any one of claims 1 to 6, characterized in that the gallium oxide thin film is composed of two-dimensionally arranged nano-pillars, the length direction of which is perpendicular to a two-dimensionally arranged plane.
8. The gallium oxide film according to claim 7, wherein the thickness of the gallium oxide film is 237-257 nm.
9. The gallium oxide film according to claim 7, wherein the gallium oxide film has an average light transmittance of > 97% in a blue light band range of 400nm to 500 nm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210366065.2A CN114990505B (en) | 2022-04-08 | 2022-04-08 | Gallium oxide film based on optical waveguide effect and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210366065.2A CN114990505B (en) | 2022-04-08 | 2022-04-08 | Gallium oxide film based on optical waveguide effect and preparation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114990505A CN114990505A (en) | 2022-09-02 |
| CN114990505B true CN114990505B (en) | 2023-08-22 |
Family
ID=83023883
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210366065.2A Active CN114990505B (en) | 2022-04-08 | 2022-04-08 | Gallium oxide film based on optical waveguide effect and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114990505B (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20130112203A (en) * | 2012-04-03 | 2013-10-14 | 인하대학교 산학협력단 | Method of manufacturing gallium oxide nanowire comprising noble metal discontinously and gallium oxide nanowire using the same method |
| KR101467118B1 (en) * | 2013-10-16 | 2014-12-01 | 조선대학교산학협력단 | METHOD OF SYNTHESIZING β??Ga2O3 NANOWIRES USING SPUTTERING TECHNIQUE |
| CN108735833A (en) * | 2018-05-30 | 2018-11-02 | 张权岳 | A kind of flexible wide spectrum photodetector of organic/inorganic pn-junction nano-array and preparation method thereof |
| CN112111711A (en) * | 2020-08-25 | 2020-12-22 | 深圳大学 | Gallium oxide nanorod, preparation method thereof and photoelectric detector |
| CN112831750A (en) * | 2021-01-04 | 2021-05-25 | 广东省科学院中乌焊接研究所 | Method for growing gallium oxide film on substrate and gallium oxide film |
| CN112921271A (en) * | 2021-01-11 | 2021-06-08 | 浙江大学 | Erbium-doped gallium oxide film and preparation method and application thereof |
| CN113066902A (en) * | 2021-03-25 | 2021-07-02 | 北京邮电大学 | Method for regulating and controlling photoelectric response performance of epsilon-phase gallium oxide through oxygen vacancy concentration |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2018103647A1 (en) * | 2016-12-08 | 2018-06-14 | 西安电子科技大学 | Method for fabricating ultraviolet photodetector based on ga2o3 material |
-
2022
- 2022-04-08 CN CN202210366065.2A patent/CN114990505B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20130112203A (en) * | 2012-04-03 | 2013-10-14 | 인하대학교 산학협력단 | Method of manufacturing gallium oxide nanowire comprising noble metal discontinously and gallium oxide nanowire using the same method |
| KR101467118B1 (en) * | 2013-10-16 | 2014-12-01 | 조선대학교산학협력단 | METHOD OF SYNTHESIZING β??Ga2O3 NANOWIRES USING SPUTTERING TECHNIQUE |
| CN108735833A (en) * | 2018-05-30 | 2018-11-02 | 张权岳 | A kind of flexible wide spectrum photodetector of organic/inorganic pn-junction nano-array and preparation method thereof |
| CN112111711A (en) * | 2020-08-25 | 2020-12-22 | 深圳大学 | Gallium oxide nanorod, preparation method thereof and photoelectric detector |
| CN112831750A (en) * | 2021-01-04 | 2021-05-25 | 广东省科学院中乌焊接研究所 | Method for growing gallium oxide film on substrate and gallium oxide film |
| CN112921271A (en) * | 2021-01-11 | 2021-06-08 | 浙江大学 | Erbium-doped gallium oxide film and preparation method and application thereof |
| CN113066902A (en) * | 2021-03-25 | 2021-07-02 | 北京邮电大学 | Method for regulating and controlling photoelectric response performance of epsilon-phase gallium oxide through oxygen vacancy concentration |
Non-Patent Citations (1)
| Title |
|---|
| 张士英等.棒状氧化镓的合成和发光性质研究.《功能材料》.2008,第39卷(2008年第4期),第681-683页. * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114990505A (en) | 2022-09-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Suh et al. | Semiconductor to metal phase transition in the nucleation and growth of VO 2 nanoparticles and thin films | |
| Subba Reddy et al. | Effect of film thickness on the structural morphological and optical properties of nanocrystalline ZnO films formed by RF magnetron sputtering | |
| Triboulet et al. | Epitaxial growth of ZnO films | |
| Zhu et al. | Low temperature annealing effects on the structure and optical properties of ZnO films grown by pulsed laser deposition | |
| Molinari et al. | Visible photoluminescence in amorphous SiN x thin films prepared by reactive evaporation | |
| Zhou et al. | Growth of amorphous-layer-free microcrystalline silicon on insulating glass substrates by plasma-enhanced chemical vapor deposition | |
| US8222055B2 (en) | Silicon nitride layer for light emitting device, light emitting device using the same, and method of forming silicon nitride layer for light emitting device | |
| Susner et al. | Catalyst-free ZnO nanowires on silicon by pulsed laser deposition with tunable density and aspect ratio | |
| CN114990505B (en) | Gallium oxide film based on optical waveguide effect and preparation method thereof | |
| Esposito et al. | Annealing effects on PECVD-grown Si rich aSiNx thin films | |
| CN109082631B (en) | Ga2O3Transparent conductive film and preparation method thereof | |
| Abdulrahman | Study the optical properties of the various deposition solutions of ZnO nanorods grown on glass substrate using chemical bath deposition technique | |
| CN100356642C (en) | C-MgxZn1-xO/MgO multi-quantum sink heterogeneous structural materials and producing process thereof | |
| CN108231545A (en) | It is grown in InN nano-pillar epitaxial wafers on copper foil substrate and preparation method thereof | |
| KR101738573B1 (en) | ZnOnanorods array, and method for preparing thereof | |
| Guo et al. | Density-controlled growth of ZnO nanowires via nanoparticle-assisted pulsed-laser deposition and their optical properties | |
| Guanghua et al. | Effect of power variation on microstructure and surface morphology of HgCdTe films deposited by RF magnetron sputtering | |
| Tang et al. | Optical characterization of ZnO thin films deposited by RF magnetron sputtering method | |
| Wu et al. | Growth and characterization of epitaxial ZnO nanowall networks using metal organic chemical vapor deposition | |
| Sahoo et al. | Band gap variation in copper nitride thin films | |
| CN112111711A (en) | Gallium oxide nanorod, preparation method thereof and photoelectric detector | |
| Lobanov et al. | Epitaxial GaN layers formed on langasite substrates by the plasma-assisted MBE method | |
| TWI450320B (en) | A process for the preparation of photo luminescent nanostructured silicon thin films | |
| KR101335722B1 (en) | Manufacturing method of nanorods by hydrothermal process and thin film formation by atomic layer deposition, nanorods made by the same, and the device comprising the same | |
| KR100576984B1 (en) | Method of single crystal ZnO thin film growth on Si substrate using nitride intermediate layer |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |