586007 _1_圓 (發明説明應敘明：發明所屬之技術領域、先前技術、内容、實施方式及圖式簡單説明） 發明所屬之技術領域： 本發明係有關於種氮氣感測器（Hydrogen Sensor)及 其製造方法’特别疋有關於一種金-絶-半式 (Metal-Insulator-Semiconductor ； MIS)之氫氣感測器及 利用無電鍍（E 1 e c t r 〇 1 e s s P 1 a t i n g )技術製作此金-絶-半 式之氫氣感測器結構的方法。 先前技術： 氫氣感測器係一種在工業上應用相當廣泛的元件。目 如’鼠氣感測器之蕭特基（S c h 〇 t t k y )界面結構係由金-半 (Metal-Semiconductor; MS)界面所構成。然而，在蕭特基 之金-半界面結構的製作過程中，只要製程條件控制不佳， 所形成之蕭特基金-半界面的品質即會受到嚴重影響，而造 成反向漏電流（Leakage Current)增加，蕭特基能障降低， 甚至產生費米说階釘住效應（Fermi-level Pinning EffectJ 之電性現象。 於是’若將此品質不佳之蕭特基金-半界面應用於氫氣 檢測時，表面能階會降低吸附於蕭特基之金-半界面氫原子 之極化程度’而導致氫氣檢測器之氫氣檢測能力減弱甚至 喪失。另外，氫氣檢測器中之蕭特基能障降低時，亦會造 成氫氣檢測器之蕭特基能障的可變化範園減小，而使氫氣 檢測之極限與濃度範圍受到限制。 6 586007 此外，在製作蕭特基之金-半界面結構之金屬層時，一 般係採用物理性之眞空鍍膜技術。由於眞空鍍膜技術係屬 於高能量之鍍膜方法，在沈積金屬層時往往會傷害半導體 層之表面，尤其會造成電荷與缺陷的累積，對於蕭特基二 極體所需之高品質金-半界面性質係爲一大缺點。舉例而 言，以眞空蒸鍵（Vacuum Evaporati〇n)技術製備氫氣感測 元件之金屬層時’金屬材料經迅速加熱揮發成金屬原子蒸 汽而沈積於半導體層之表面時，會放出潛熱（Latent Heat) ’所釋放出之潛熱會傷害半導體層之表面。如此一 來，將會使金屬層與其下半導體層間之界面品質降低，導 致氫氣感測元件之蕭特基能障不高，進而造成此氫氣感測 元件之氫氣濃度檢測極限與範圍受到限制。 發明内容： 本發明的主要目的之一就是在提供一種氫氣感測器， 其在蕭特基金-半界面之間導入絶緣層薄膜，以金—絶半蕭 特基二極體結構來取代蕭特基金-半界面，以降低金屬層與 半導體間之表面能態密度，並改善金屬層與半導體間之界 面性質。 1 本發明之另一目的就是在提供一種具有金-絶半蕭特 基二極體結構之氫氣感測器，其中絶緣層之材料可選用伊 高溫處理過之氧化層或離子鍵較強的金屬氧化物。利用此 品質優良之絶緣層夾於金屬層與半導體層之界面間，不传 可以純化（Passivate)半導體層本質（IntrU 、 7 電荷’亦可減少金屬層在蒸鍍製程時於半導體層表面產生 額外之表面能態。 、本發明之再一目的就是在提供_種氫氣感測器之製造 万法’其係運用無電鍍技術製備金 '絶_半蕭特基二極體結 財之金屬層，可利用無電鍍製程之低溫低能鍍膜技術來 減少金屬層鍍覆時所產生之缺陷或電荷。因此，可大幅改 善蕭特基界面之品質，$而增進氫氣感測器之氫氣檢測性 厶匕 月&。586007 _1_circle (the description of the invention should be stated: the technical field to which the invention belongs, the prior art, the content, the embodiments and the drawings are briefly explained) The technical field to which the invention belongs: The present invention relates to a kind of nitrogen sensor (Hydrogen Sensor) And its manufacturing method 'specifically about a metal-insulator-semiconductor (MIS) hydrogen sensor and the use of electroless plating (E 1 ectr 〇1 ess P 1 ating) technology to make this gold- Method of absolute-half-type hydrogen sensor structure. Prior technology: A hydrogen sensor is a component that is widely used in industry. The Schottky (Schh t t ky) interface structure of the object 'mouse gas sensor is composed of a metal-semiconductor (MS) interface. However, in the production process of the Schottky gold-half interface structure, as long as the process conditions are not well controlled, the quality of the formed Schott fund-half interface will be seriously affected, causing reverse leakage current (Leakage Current ) Increases, the Schottky barrier decreases, and even Fermi-level Pinning Effect J electrical phenomenon occurs. So 'if this poor quality Schott Fund-half interface is used for hydrogen detection, The surface energy level will reduce the degree of polarization of the gold-half interface hydrogen atoms adsorbed on the Schottky ', resulting in the weakening or loss of the hydrogen detection capability of the hydrogen detector. In addition, when the Schottky barrier in the hydrogen detector decreases, It will also reduce the variable range of the Schottky barrier of the hydrogen detector, which limits the limit and concentration range of hydrogen detection. 6 586007 In addition, the metal layer of the Schottky gold-half interface structure is being produced. In general, the physical hollow coating technology is generally used. Since the hollow coating technology is a high-energy coating method, the surface of the semiconductor layer is often damaged when the metal layer is deposited. In particular, it will cause the accumulation of charges and defects, which is a major disadvantage for the high-quality gold-semi-interfacial properties required for Schottky diodes. For example, the vacuum evaporation technology (Vacuum Evaporati) technology is used to prepare hydrogen. When measuring the metal layer of a component, 'Latent heat will be released when a metal material is rapidly heated to volatilize into metal atom vapors and deposited on the surface of the semiconductor layer.' The latent heat released will damage the surface of the semiconductor layer. As a result, The quality of the interface between the metal layer and the underlying semiconductor layer will be reduced, resulting in a low Schottky energy barrier of the hydrogen sensing element, which will further limit the detection limit and range of the hydrogen concentration of the hydrogen sensing element. SUMMARY OF THE INVENTION The present invention One of the main goals of the company is to provide a hydrogen sensor that introduces an insulating film between the Schott Fund-half interface and replaces the Schott Fund-half interface with a gold-absolute Schottky diode structure. In order to reduce the surface energy density between the metal layer and the semiconductor, and improve the interface properties between the metal layer and the semiconductor. 1 Another object of the present invention is to improve For a hydrogen sensor with a gold-absolute Schottky diode structure, the material of the insulating layer can be selected from the high-temperature-treated oxide layer or the metal oxide with a strong ion bond. Use this high-quality insulation The layer is sandwiched between the interface between the metal layer and the semiconductor layer, and the essence of the semiconductor layer (IntrU, 7 charges) can be passed without passivation. It can also reduce the extra surface energy state of the metal layer on the surface of the semiconductor layer during the evaporation process. Another object of the present invention is to provide _ a kind of manufacturing method of hydrogen sensors '' which is the use of electroless plating technology to prepare gold '' absolute _ semi-Schottky diode rich metal layer, can use the electroless plating process Low temperature and low energy coating technology to reduce defects or charges generated during metal layer plating. Therefore, the quality of the Schottky interface can be greatly improved, and the hydrogen detection performance of the hydrogen sensor can be improved.
根據以上所述〈目的，本發明更提供了 一種氯氣感測 器，至少包括：-半導體基底，其中此半導體基底之材質 可爲半絶緣料化鎵（GaAS)或半絶緣㈣化銦（Inp)等；一 半導體缓衝層位於上述之半導體基底上，丨中此半導體缓 衝層之材質可爲未摻雜之砷化鎵或磷化銦等；一半導體薄 膜位於上述之半導體缓衝層上，纟中此半㈣薄膜之材質 可爲η型之砷化鎵或磷化銦等；一歐姆接觸（Oh — Contact)金屬電極位於部分之半導體薄膜上，其中此歐姆 接觸金屬電極之材質可爲金_鍺_鎳（Au Ge Ni)合金或金_ 鍺（Au Ge)合金等，一絶緣層位於另一部分之半導體薄膜 上，其中此絶緣層之材質可爲上述半導體薄膜之氧化物， 或者爲二氧化鈇（1^〇2)或氧化辞（Zn〇)等；以及一無電鍍式 蕭特基接觸金屬電極位於上述之絶緣層上，其中此無電鍍 式蕭特基接觸金屬電極之材質可爲鈀（pd)、鉑（pt)、銥 (ΐΓ )、錢（Rh)、奶（Ru)、或⑨-銀（Pd-Ag)合金。 8 根據以上所述之目的 4» ϋ η 的本發明另外更提供了一種氫氣 2器之製造方法，至少包肖：提供-半導體基底，其中 义、導體基辰上至少已形成依序堆疊之-半導體缓衝層位 :此半導體基底上以及一半導體薄膜；形成一歐姆接觸金 屬電極位於部分之半導體薄膜上；形成_絶緣層位於另一 邛刀〈半導體薄膜上；以及形成一無電鍍式蕭特基接觸金 屬電極位於上述之絶緣層上。其中，待歐姆接觸金屬電極 形成後，《至少包括進行—退火步驟，藉以使此歐姆接觸 金屬電極中之金屬能擴散深入至上述之半導體薄膜中。 本發明在蕭特基接觸金屬電極_半導體薄膜界面間導 入絶緣層，可以鈍化半導體薄膜内之本質缺陷，並可降低 半導體薄膜之表面能態數目，進而達到提升界面品質的目 的。因此，可大幅改善氫氣感測器之氫氣感測表現。此外， 由於本發明利用無電鍍技術製備蕭特基接觸金屬電極，藉 由無電鍍技術之低溫低能特點，亦可增進氫氣感測器之^ 氣檢測能力。 實施方式： 本發明揭露一種氫氣感測器及其製造方法，其係利用 金_絶-半蕭特基二極體結構取代習知金-半蕭特基界面結 構。因此，可達到改善金屬層與半導體間之界面性質的目 的。此外’本發明更利用無電鍍技術製備蕭特基二極體結 構之金屬層，以獲得高品質之蕭特基界面。爲了使本發明 之敘述更加詳盡與完備，可參照下列描述並配合第1圖至 586007 第6圖之圖示。 半導二?’第1圖係繪示本發明之金屬·絶緣層. μ a至上半）式氫氣感測器100 ’由下而上之結構依 序爲··-半絶緣型之半導體基底1〇2;厚度介於。.…至 間，未摻雜之半導體缓衝層1〇4;厚度介於〇1^ 主堪間’掺雜濃度介^ a10、3至5XlG'm 3間之 半導體薄膜106; — Μ声人认Λ m ^ m s- ί. ^ >l .1以"1至5.〇以111 間之歐姆 接觸金屬電極1〇8;厚度介於2〇“ 1〇According to the above-mentioned object, the present invention further provides a chlorine gas sensor, which at least includes:-a semiconductor substrate, wherein the material of the semiconductor substrate may be semi-insulating gallium (GaAS) or semi-insulating indium halide (Inp) Etc .; a semiconductor buffer layer is located on the above semiconductor substrate, and the material of the semiconductor buffer layer may be undoped gallium arsenide or indium phosphide, etc .; a semiconductor thin film is located on the above semiconductor buffer layer, The material of this half-thickness film can be n-type gallium arsenide or indium phosphide; an ohm contact (Oh — Contact) metal electrode is located on a part of the semiconductor film, and the material of the ohmic contact metal electrode can be gold _Ge_Ni (Au Ge Ni) alloy or Au_German (Au Ge) alloy, etc., an insulating layer is located on another part of the semiconductor film, wherein the material of this insulating layer can be the oxide of the semiconductor film, or two Hafnium oxide (1 ^ 〇2) or oxide (Zn〇), etc .; and an electroless Schottky contact metal electrode is located on the above-mentioned insulating layer, wherein the material of the electroless Schottky contact metal electrode may be (Pd), platinum (Pt), iridium (ΐΓ), money (Rh), milk (Ru), or ⑨- silver (Pd-Ag) alloy. 8 According to the above-mentioned purpose 4 »4 η, the present invention further provides a method for manufacturing a hydrogen 2 device, at least including: providing-a semiconductor substrate, in which at least a sequential stack has been formed on the conductor and the conductor- Semiconductor buffer layer: on this semiconductor substrate and a semiconductor film; forming an ohmic contact metal electrode on a part of the semiconductor film; forming an insulating layer on another trowel <semiconductor film; and forming an electroless Schott The base contact metal electrode is located on the above-mentioned insulating layer. Wherein, after the formation of the ohmic contact metal electrode, "at least includes a step of performing-annealing, so that the metal in this ohmic contact metal electrode can diffuse into the above-mentioned semiconductor thin film. The invention introduces an insulating layer between the Schottky contact metal electrode and the semiconductor film interface, which can passivate the intrinsic defects in the semiconductor film, and can reduce the number of surface energy states of the semiconductor film, thereby achieving the purpose of improving the interface quality. Therefore, the hydrogen sensing performance of the hydrogen sensor can be greatly improved. In addition, since the Schottky contact metal electrode is prepared by the electroless plating technology of the present invention, the low temperature and low energy characteristics of the electroless plating technology can also improve the gas detection capability of the hydrogen sensor. Embodiments: The present invention discloses a hydrogen sensor and a manufacturing method thereof, which replace a conventional gold-semi-Schottky interface structure with a gold-absolute-semi-Schottky diode structure. Therefore, the object of improving the interface property between the metal layer and the semiconductor can be achieved. In addition, the present invention further uses an electroless plating technique to prepare the metal layer of the Schottky diode structure to obtain a high-quality Schottky interface. In order to make the description of the present invention more detailed and complete, reference may be made to the following descriptions in conjunction with the diagrams in Figures 1 to 586007 and Figure 6. Semiconducting II? 'The first figure is the metal and insulating layer of the present invention. Μ a to the top half) type hydrogen sensor 100' The structure from bottom to top is in order ..-semi-insulating semiconductor substrate 1 〇2; thickness is between. ... In the meantime, the undoped semiconductor buffer layer 104; the thickness is between 0.01 and the semiconductor film 106 between doping concentration ^ a10, 3 to 5 × 1G'm 3; — Μ 声 人Recognize Λ m ^ m s- ί. ^ ≫ l .1 contact the metal electrode 108 with " 1 to 5.0 in 111 ohms; the thickness is between 20 and 10
以及厚度介於〇·。…至^間，無電鍍之㈣ 接觸金屬電極112 ’其中歐姆接觸金 接觸金屬電極⑴彼此鄭近但不相互接觸。在本發= 氣感測器100中，丰A + 尽贫月又虱 化銦；半導體緩衝=Μ之材料可爲坤化鎵或， 化銦；半導體薄膜:心：：科可爲未摻雜之神化鎵或嶙 銦；歐姆接觸全Π 可爲n型之神化鎵或碑化 鍺合金;絶緣層110::之材料可爲金♦線合金或金- 二氧化妖、或氧《 爲半導體薄膜106之氧化物、And the thickness is between 0 ·. … To ^, electroless plated contact metal electrode 112 ′ where ohmic contact gold contacts metal electrode 郑 are close to each other but not in contact with each other. In the present invention = the gas sensor 100, the abundance of A + is depleted and the indium is inactivated; the material of the semiconductor buffer = M may be gallium or indium; the semiconductor thin film: core :: Ke may be undoped The deified gallium or indium; the ohmic contact can be n-type deified gallium or indium germanium alloy; the material of the insulating layer 110 :: can be gold wire alloy or gold-dioxide, or oxygen Oxide of 106,
可爲免、始、& Γ且蕭特基接觸金屬電極112之材料 自&、錄、句、或鈀_銀合金。 &本發明之較佳眘 先以金屬有機化與A ，氫氣感測器1 0 0之製作首 法(職)在半雄絡予 沈積法(M0CVD)或分子束磊晶成長 良好，厚度/ 嫁之半導體基底102上成長-品質 及厚度爲i i、ami未摻雜砷化鎵作爲半導體缓衝層“4 〈 n型砷化鎵作爲半導體薄膜106。利用光 10 586007 罩（Mask)、微影（Li thc^r u 、# graphy)、眞空蒸鍍技術與剝離技 術於半導體薄膜1〇6表面先形成一金-鍺合金 膜，經退火熱處理後形成歐姆接觸電極“Ο上述退火敎 處理之溫度介於3 0 0。。至5〇砣之間，且退火熱處理之時間 介於3〇秒至5分鐘之間。接著，再以濕蝕刻（ffet_etching) 技術進行元件隔離，經清洗與㈣㈣去除表面雜質後， 再以熱氧化法（Thermal0xidati〇n)於半導體薄膜ι〇6之另 一部分上形成厚度約6〇 A之砷化鎵氧化層作爲絶緣層The material of Schottky contact metal electrode 112 may be free, starting, & Γ, &, &, & Γ, & Γ, & & The preferred method of the present invention is to first use metal organication and A, hydrogen sensor 100 to produce the first method (job) in the semi-androgynous pre-deposition method (MOCVD) or molecular beam epitaxial growth is good, thickness / Growth on the semiconductor substrate 102-quality and thickness ii, ami undoped gallium arsenide as semiconductor buffer layer "4 <n-type gallium arsenide as semiconductor thin film 106. Use light 10 586007 Mask, lithography (Li thc ^ ru, #graphy), vacuum evaporation technology and stripping technology first form a gold-germanium alloy film on the surface of the semiconductor thin film 106, and after annealing and heat treatment, an ohmic contact electrode is formed. At 3 0 0. . To 50 ° F, and the annealing heat treatment time is between 30 seconds to 5 minutes. Then, wet isolation (ffet_etching) technology is used to isolate the components. After cleaning and cleaning, the surface impurities are removed, and then a thermal oxidation method (Thermal Oxidation) is used to form a thickness of about 60 Å on another part of the semiconductor thin film ι06. GaAs oxide layer as insulation layer
11 〇上述之熱氧化法係於合成空氣之環境下進行氧化絶緣 薄膜的成長；其溫度介於1001〇至5 0 0 1〇之間，並且時間介 於2 〇分鐘至5小時之間，其中合成空氣至少包括氧氣 (〇2)。此外，絶緣層11〇亦可利用微影、光罩、眞空蒸鍍 技術與剝離技術，或者可利用微影、光罩、濺鍍（Spu t t e r i ng ) 技術與剝離技術來加以製作。最後，再配合光罩、微影、 無電鍍與剥離技術沉積鈀金屬於絶緣層i〇上，形成蕭特 基接觸金屬電極llz。此外，蕭特基接觸金屬電極ιΐ2亦110. The above thermal oxidation method is for the growth of oxidized insulating films in an environment of synthetic air; its temperature is between 1001 and 5 0 1 0, and the time is between 20 minutes and 5 hours, of which The synthetic air includes at least oxygen (0 2). In addition, the insulating layer 110 can also be fabricated by using lithography, photomask, air evaporation deposition technology and stripping technology, or by using lithography, photomask, sputtering (Sputt e r ng) technology and stripping technology. Finally, palladium metal is deposited on the insulating layer i0 in cooperation with photomask, lithography, electroless plating, and stripping techniques to form a Schottky contact metal electrode 11z. In addition, Schottky contacts metal electrodes ιΐ2.
可利用微影、光罩、敏化、活化、無電鍍、與剝離技術來 加以製作。 上述之敏化、活化步驟係將半導體基底i 〇 2連同其上 之堆疊結構依序浸入例如酸性含亞錫離子之敏化溶液及酸 性含飽離子之活化溶液中各5分鐘至1 〇分鐘，再利用例如 去離子水進行清洗。 利用無電鍍技術製作蕭特基接觸金屬電極i i 2時，係 586007 將半導體基底1〇2連同其上之堆疊結構一併浸入控溫之無 電鍍鍵浴中以析鍍金屬層’再以去離子水清洗之。本發明 所採用之無電鍍鍍浴包括擬析鍍金屬前驅鹽 (Precursor)、還原劑（Reducing Agent)、錯合劑 (Co mplexing Agent)、pH 緩衝劑（Buffer)、安定劑 (Stabilizer)、以及光免劑（Brightening Agent)等成分。 其中，擬析鍍金屬前驅鹽至少包括欲析鍍金屬之卣化物、 硝酸鹽、或醋酸鹽類等；還原劑至少包括聯胺 (Hydrazine)、甲酸（Formaldehyde)、次鱗酸鹽 (Hyp〇ph〇sphite)、棚氫化物（Borohydride)、或具有還原 性之醣類等；錯合劑至少包括硝酸鹽、銨鹽、硫酸鹽、氰 酸鹽、乙酸鹽、甲酸鹽、碳酸鹽、磷酸鹽、硼酸鹽、鹵鹽、 乙二胺 （E t hy 1 e n e d i am i n e )、 四甲基乙二胺 (Tetramethylethylenediamine)、或乙二胺四乙酸 (Ethylened i ami ne Tetraacetic Acid, EDTA)等；安定劑 至少包括硫尿（Thiourea)或硫二甘酸（Thi〇diglyc〇1 u wid)等；pH緩衝劑至少包括鹼性之氫氧化銨、磷酸鹽、 碳酸鹽、或硼酸鹽等，或者酸性之甲酸、乙酸、草酸（〇xal u Acid)、酒石酸（Tartaric Acid)、或擰檬酸（Citric Acid) 等’而光党劑則至少包括檐精（Saccharin)等。本發明之無 電鍍鍍浴的pH値控制在介於8至u之間，或者控制在介 於1至3之間。此外，爲維持電鍍鍍浴之穩定性與析鍍速 率及品質，本發明之無電鍍鍍浴中尚可加入其他添加物質。 586007 本實施例所採用之無電鍍鍍浴系統，係以甲醛（HCHO) 爲還原劑，於析鍍基材表面之活性位置進行化學反應，將 鍍浴中由氣化鈀（PdC 12)前驅鹽所提供之鈀離子還原並沈 積於基材表面。其反應爲：It can be fabricated using lithography, photomask, sensitization, activation, electroless plating, and stripping techniques. The above sensitization and activation steps are sequentially immersing the semiconductor substrate i 02 together with the stacked structure thereon, for example, an acidic stannous ion-containing sensitizing solution and an acidic saturated ion-containing activating solution for 5 to 10 minutes each, It is then washed with, for example, deionized water. When using the electroless plating technology to make the Schottky contact metal electrode ii 2, the system 586007 immerses the semiconductor substrate 102 together with the stacked structure thereon in a temperature-controlled electroless plating key bath to deposit a metal layer and then deionize it. Wash it with water. The electroless plating bath used in the present invention includes a pseudo-metal plating precursor (Precursor), a reducing agent (Reducing Agent), a complex agent (Co mplexing Agent), a pH buffer (Buffer), a stabilizer (Stabilizer), and a light Ingredients such as Brightening Agent. Among them, the precursor metal to be electroplated includes at least the halide, nitrate, or acetate of the metal to be electroplated; the reducing agent includes at least Hydrazine, Formic acid, and Hypophate. 〇sphite), shed hydride (Borohydride), or reducing sugars, etc .; complexing agents include at least nitrate, ammonium, sulfate, cyanate, acetate, formate, carbonate, phosphate, Borates, halides, Ethy 1 enedi am ine, Tetramethylethylenediamine, or Ethylened i ami ne Tetraacetic Acid (EDTA), etc .; stabilizers at least Including Thioura or Thiodiglycoic acid, etc .; pH buffering agents include at least basic ammonium hydroxide, phosphate, carbonate, or borate, or acidic formic acid, acetic acid , Oxalic acid (tarxic acid), tartaric acid, or citric acid (Citric Acid), etc., and the light party agents at least include eucalyptus (Saccharin) and so on. The pH of the electroless plating bath of the present invention is controlled between 8 and u, or between 1 and 3. In addition, in order to maintain the stability of the electroplating bath and the rate and quality of the electroplating bath, other additives can be added to the electroless plating bath of the present invention. 586007 The electroless plating bath system used in this example uses formaldehyde (HCHO) as a reducing agent to perform a chemical reaction at the active position on the surface of the plating substrate. The plating bath is pre-salted with vaporized palladium (PdC 12) The provided palladium ions are reduced and deposited on the surface of the substrate. The response is:
Pd2 + (aq) + HCHO(aq) + H2〇^Pd(s)+HCOOH(aq) + 2H + (aq) 爲維持鍍浴之穩定性與其析鍍速率及品質，本系統之 鍍浴中尚含有其他添加物質。鍍浴組成如下： HCH0 0 · 2〜2 · 〇 μ Μ ΗΝ〇3 HCOOH 〇·〇4〜〇·4 μPd2 + (aq) + HCHO (aq) + H2〇 ^ Pd (s) + HCOOH (aq) + 2H + (aq) In order to maintain the stability of the plating bath and its plating rate and quality, Contains other additives. The composition of the plating bath is as follows: HCH0 0 · 2 ~ 2 · 〇 μ Μ Ν〇3 HCOOH 〇〇〇4〜〇 · 4 μ
Saccharin 0.002Μ 在鍍覆蕭特基接觸金屬電極112時，無電鍍步驟之析 鍍溫度介於2 0 1〇至7 〇 °C之間，且析鍍時間介於χ分鐘至工 小時之間。 請參照第2 ( a )圖與第2 ( b )圖，且請一併參照第}圖之 圖示，其中第2 ( a )圖與第2 ( b )圖係繪示本發明之一較佳實 施例之氫氣感測器的電荷分佈圖與其對應能帶圖，其中第 2(a)圖表示未引入氫氣，而第2(b)圖表示引入氫氣後之變 化。在引入氫氣之前，氫氣感測器1 0 0中蕭特基接觸金屬 電極II2之他金屬與半導體薄膜1〇6之η型砰化鎵會因電 子流動而產生空乏區；待平衡後，在金屬-氧化層-半導體 586007 <間會形成一蕭特基能障，如第2 (a)圖所示。引入氬氣之 後’由於蕭特基接觸金屬電極之鈀金屬對氫氣特有之 催化性以及選透性，可將氫分子分解爲氫原子並擴散穿透 至蕭特基接觸金屬電極II2之鈀金屬層與絶緣層之珅 化鎵氧化層的界面上，而形成氫原子層。此氫原子層因内 建電場而被極化，而形成氫原子極化層，並形成具有反向 黾劳之反向偶極層（Dipolar Layer)，而使空乏區寬度縮減 並降低蕭特基能障高度，如第2 ( b )圖所示。隨著環境中氫 氣濃度之提升，位於蕭特基接觸金屬電極之鈀金屬與 絶緣層11〇之砷化鎵氧化層中之氫吸附量亦會增加，氫氣 感測器1〇〇之蕭特基能障下降，故電流增加。如此一來， 便可藉由電流之增加量來檢測環境中之氫氣含量。 凊參照第3圖，第3圖係繪示習知金-半式氫氣感測器 於14 〇 C下之虱軋感測表現。習知金_半式氫氣感測器，在 低濃度之氫氣環境中，感測效果並不理想，需增加氫氣濃 度至1 %時，其正、反向電流方有較明顯之變化。此種現 象主要疋因爲無絶緣層存在之金-半蕭特基界面，會累積較 多之表面電荷與缺陷，界面品質不佳，如此一來會導致界 面氫原子之極化程度降低，|氫氣感測器之氫氣感測效果 下降故需較在南之氫氣濃度環境之中才有明顯的電性變 化。因此，此類結構之氫氣感測器其氫氣濃度檢限與範圍 往往受到較大的限制。另外，相關研究並指出單純金半界 面如本實施例之鈀-砷化鎵系統，其中鈀與砷、鎵元素會相 互擴散（Inter-diffusion)，甚至形成鈀砷鎵之化合物，導 致蕭特基界面消失，亦會使其氫氣檢測表現不佳。 凊參照第4圖，第4圖係繪示本發明之一較佳實施例 <鈀-砷化鎵氧化層-砷化鎵式氫氣感測器於丄4^^下之氫 氣感測表現。本發明之氫氣感測器僅在ls ppm氫氣/空氣 <低濃度氫氣環境下即出現感測效果，而且正向與反向電 流之變化量皆隨氫氣濃度增加而增大，對氫氣具有極佳2 檢測表現。即使將氫氣濃度提升至1%氫氣/空氣，本發明 之氫氣感測器的電流特性仍可維持二極體之整流特性，且 尚未達到飽和之感測極限，故可檢測更高之氫氣濃度與範 圍。 本發明之一特徵是因爲導入高品質絶緣層於蕭特基接 觸金屬電極-半導體薄膜界面間，可以純半導 本質缺陷：降低半導體薄膜之表面能態數目導進 飾半導體薄膜表面之效果。如此一來，不僅可有效防止例 如鈀、砷、鎵之相互擴散，更可提升界面品質，大幅改善 氫氣感測器之氫氣感測表現。 請參照第5圖，第5圖係繪示本發明之一較佳實施例 之鈀-砷化鎵氧化層-砷化鎵式氫氣感測器的蕭特基能障高 度對空氣中之氫氣濃度關係圖。本發明之氫氣感測器的蕭 特基能障隨氫氣濃度升高而降低。於，本發明之 氫氣感測器在合成空氣中之蕭特基能障約高度爲9 3 8毫電 子伏特（meV)，當氫氣濃度由ls ppm提升至1%時，蕭特 586007 基能障下降約70 raeV。 請參照第6圖，第6圖係緣示本發明之一較佳實施例 之鈀-砷化鎵氧化層_砷化鎵式氫氣感測器於下氫氣 感測之飽和靈敏度對氫氣濃度之關係圖。飽和靈敏度 (saturatic5n Sensitivity)定義爲氫氣存在之下， ^ * 化對基準電流之比値，亦即(lH2-Iair)/I…。在第6圖中乂 — 本發明之氫氣感測器的$敏度隨氫氣濃度增高而增加。正 向偏壓施加越小，其氫氣飽和靈敏度越高。於o wv正向 偏壓下，對15 ppm氫氣含量所測得之靈敏度可達U N， _ 於1 %氫氣含量所測得之靈敏度則可高達26〇 %。 综上所述，本發明之一優點就是因爲本發明於金屬-半 導體蕭特基接合界㊆間加入絶緣層結構，可大幅改進金屬— 半導體蕭特基接合界面之品質。因此，可達到提升氫氣感 測器之氫氣檢測能力的目的，並可使氫氣感測器具有更低 之氫氣檢測濃度，擴大氫氣偵檢之範圍。 本發明之又一優點就是因爲本發明之氫氣感測器可適 用於高溫下之氫氣檢測，感測氫氣濃度範圍大，具有發展 爲智慧型感測器之優勢。 · 本發明之又一優點就是因爲利用無電鍍技術製造金屬 -絶緣層-半導體式氫氣感測器，具有設備簡單、成本低廉、 操作容易、節省能源且可大量連續化生產等優點。而且， 無電鍍技術不僅與半導體製程相容性極大，更具有低溫低 能之特點，而可增進氫氣感測器之檢測能力。 16 586007 如熟悉此技術之人員所瞭解的，以上所述僅爲本發明 之較佳實施例而已，並非用以限定本發明之申請專利範 . 園；凡其它未脱離本發明所揭示之精神下所完成之等效改 · 變或修飾，均應包含在下述之申請專利範圍内。 圖式簡單説明： 第1圖係繪示本發明之一較佳實施例之氫氣感測器結 - 構的示意圖； 第2(a)圖與弟2(b)圖係緣示本發明之一較佳實施例之 氫氣感測器的電荷分佈圖與其對應能帶圖，其中第2 ( a )圖 ® 表示未引入氫氣，而第2(b)圖表示引入氫氣後之變化； 第3圖係繪示習知金-半式氫氣感測器於1 4 〇亡下之氫 氣感測表現； 第4圖係繪示本發明之一較佳實施例之鈀··砷化鎵氧化 層-珅化鎵式氫氣感/則器於14 0 C下之氫氣感測表現； 第5圖係繪示本發明之一較佳實施例之鈀-砷化鎵氧化 層-砷化鎵式氫氣感測器的蕭特基能障高度對空氣中之氫 氣濃度關係圖；以及 第6圖係繪示本發明之一較佳實施例之鈀-坤化鎵氧化 · 層-砷化鎵式氫氣感測器於140 °C下氫氣感測之飽和靈敏度 對氫氣濃度之關係圖。 圖號對照説明： 100 氫氣感測器 1G 2 半導體基底 104半導體缓衝層 106 半導體薄膜 17 586007 108 歐姆接觸金屬電極 112 蕭特基接觸金屬電極 110 絶緣層Saccharin 0.002M When the Schottky contact metal electrode 112 is plated, the precipitation temperature during the electroless plating step is between 210 and 70 ° C, and the precipitation time is between χ minutes and working hours. Please refer to FIG. 2 (a) and FIG. 2 (b), and also refer to the illustration of FIG.}, Where FIG. 2 (a) and FIG. 2 (b) are drawings showing one comparison of the present invention. The charge distribution diagram of the hydrogen sensor of the preferred embodiment and its corresponding energy band diagram, wherein FIG. 2 (a) shows that no hydrogen is introduced, and FIG. 2 (b) shows changes after the introduction of hydrogen. Before the introduction of hydrogen, the Schottky contacting the metal electrode II2 with other metals in the hydrogen sensor 100 and the n-type gallium palladium on the semiconductor thin film 106 will generate empty regions due to the flow of electrons; -Oxide layer-Semiconductor 586007 A Schottky energy barrier will be formed, as shown in Fig. 2 (a). After the introduction of argon, due to the unique catalytic and selective permeability of the palladium metal of the Schottky contact metal electrode to hydrogen, hydrogen molecules can be decomposed into hydrogen atoms and diffused through the palladium metal layer of the Schottky contact metal electrode II2. At the interface with the gallium halide oxide layer of the insulating layer, a hydrogen atom layer is formed. This hydrogen atom layer is polarized due to the built-in electric field to form a hydrogen atom polarization layer and form a reverse dipolar layer with reversed labor, thereby reducing the width of the empty region and reducing the Schottky. Barrier height, as shown in Figure 2 (b). With the increase of hydrogen concentration in the environment, the amount of hydrogen adsorption in the palladium metal of the Schottky contact metal electrode and the gallium arsenide oxide layer of the insulating layer 11 will also increase. The Schottky of the hydrogen sensor 100 The energy barrier decreases, so the current increases. In this way, the amount of hydrogen in the environment can be detected by the increase of the current.凊 Refer to Fig. 3, which shows the performance of the tick detection of the conventional gold-half hydrogen sensor at 14 ° C. Xijin_Semi-type hydrogen sensor, the sensing effect is not ideal in a low-concentration hydrogen environment. When the hydrogen concentration needs to be increased to 1%, its positive and negative currents will change significantly. This phenomenon is mainly because the gold-semi-Schottky interface without an insulating layer will accumulate more surface charges and defects, and the interface quality is not good. In this way, the polarization degree of the hydrogen atom at the interface will be reduced, | Hydrogen The hydrogen sensing effect of the sensor decreases, so it needs to have obvious electrical changes compared to the hydrogen concentration environment in the south. Therefore, the detection limit and range of the hydrogen concentration of a hydrogen sensor of this type are often limited. In addition, related studies have also pointed out that the pure gold half interface is like the palladium-gallium arsenide system of this embodiment, in which palladium, arsenic, and gallium elements can inter-diffusion, and even form palladium-arsenic-gallium compounds, leading to Schottky The disappearance of the interface will also make its hydrogen detection poor.凊 Referring to FIG. 4, FIG. 4 is a diagram illustrating a hydrogen gas sensing performance of a palladium-gallium arsenide oxide-gallium arsenide-type hydrogen sensor at 丄 4 ^^ according to a preferred embodiment of the present invention. The hydrogen sensor of the present invention has a sensing effect only in an environment of ls ppm hydrogen / air < low concentration hydrogen, and the change amount of the forward and reverse currents increases with the increase of the hydrogen concentration, which has extremely high effect on hydrogen. Good 2 detection performance. Even if the hydrogen concentration is increased to 1% hydrogen / air, the current characteristics of the hydrogen sensor of the present invention can still maintain the rectification characteristics of the diode, and it has not yet reached the sensing limit of saturation, so it can detect higher hydrogen concentrations and range. One of the characteristics of the present invention is that the introduction of a high-quality insulating layer between the Schottky contact metal electrode and the semiconductor film interface can be a pure semiconducting essential defect: reducing the number of surface energy states of the semiconductor film and guiding the effect of decorating the surface of the semiconductor film. In this way, it can not only effectively prevent the interdiffusion of, for example, palladium, arsenic, and gallium, but also improve the interface quality and greatly improve the hydrogen sensing performance of the hydrogen sensor. Please refer to FIG. 5. FIG. 5 shows the Schottky barrier height of the palladium-gallium arsenide oxide layer-gallium arsenide hydrogen sensor to the hydrogen concentration in the air according to a preferred embodiment of the present invention. relation chart. The Schottky barrier of the hydrogen sensor of the present invention decreases as the hydrogen concentration increases. Therefore, the Schottky barrier in the synthetic air of the hydrogen sensor of the present invention has a height of about 93.8 millielectron volts (meV). When the hydrogen concentration is increased from ls ppm to 1%, the Schottky 586007 base barrier Dropped about 70 raeV. Please refer to FIG. 6. FIG. 6 shows the relationship between the saturation sensitivity of the palladium-gallium arsenide oxide layer and the hydrogen concentration in the lower hydrogen sensing of a palladium-gallium arsenide oxide layer according to a preferred embodiment of the present invention. Illustration. The saturation sensitivity (saturatic5n Sensitivity) is defined as the ratio of ^ * to the reference current in the presence of hydrogen, which is (lH2-Iair) / I .... In Figure 6, 乂 — the sensitivity of the hydrogen sensor of the present invention increases as the hydrogen concentration increases. The smaller the forward bias is applied, the higher its sensitivity to hydrogen saturation. Under o wv forward bias, the sensitivity measured for 15 ppm hydrogen content can reach U N, and the sensitivity measured for 1% hydrogen content can reach 26%. In summary, one of the advantages of the present invention is that the present invention can greatly improve the quality of the metal-semiconductor Schottky junction interface by adding an insulating layer structure between the metal-semiconductor Schottky junction boundaries. Therefore, the purpose of improving the hydrogen detection capability of the hydrogen sensor can be achieved, and the hydrogen sensor can have a lower hydrogen detection concentration, and the scope of hydrogen detection can be expanded. Another advantage of the present invention is that the hydrogen sensor of the present invention can be applied to the detection of hydrogen at high temperature, has a wide range of hydrogen concentration, and has the advantage of developing into a smart sensor. · Another advantage of the present invention is that the metal-insulating layer-semiconductor hydrogen sensor is manufactured using electroless plating technology, which has the advantages of simple equipment, low cost, easy operation, energy saving, and large-scale continuous production. In addition, electroless plating technology not only has great compatibility with the semiconductor manufacturing process, but also has the characteristics of low temperature and low energy, and can improve the detection capability of the hydrogen sensor. 16 586007 As understood by those familiar with this technology, the above is only a preferred embodiment of the present invention, and is not intended to limit the scope of patent application for the present invention. Park; all others without departing from the spirit of the present invention All equivalent changes, alterations or modifications completed below shall be included in the scope of patent application described below. Brief description of the drawings: Figure 1 is a schematic diagram showing the structure of a hydrogen sensor according to a preferred embodiment of the present invention; Figures 2 (a) and 2 (b) show one of the inventions. The charge distribution diagram of the hydrogen sensor of the preferred embodiment and its corresponding energy band diagram, where Figure 2 (a) shows no hydrogen introduced, and Figure 2 (b) shows the changes after the introduction of hydrogen; Figure 3 shows Shows the hydrogen sensing performance of a conventional gold-half hydrogen sensor at 140 ° C; Figure 4 shows a palladium ·· GaAs oxide layer-thallium oxide, which is a preferred embodiment of the present invention. The hydrogen sensing performance of the gallium hydrogen sensor at 14 0 C; FIG. 5 shows the palladium-gallium arsenide oxide layer-gallium arsenide hydrogen sensor according to a preferred embodiment of the present invention. Schottky Barrier Height vs. Hydrogen Concentration in the Air; and Figure 6 shows a palladium-gallium oxide-layer-gallium arsenide-type hydrogen sensor at 140 according to a preferred embodiment of the present invention. Relationship between saturation sensitivity of hydrogen sensing and hydrogen concentration at ° C. Comparative description of drawing numbers: 100 hydrogen sensor 1G 2 semiconductor substrate 104 semiconductor buffer layer 106 semiconductor film 17 586007 108 ohm contact metal electrode 112 Schottky contact metal electrode 110 insulation layer