CN113186512A

CN113186512A - Method for growing anisotropic film and gas cluster reactor

Info

Publication number: CN113186512A
Application number: CN202110447250.XA
Authority: CN
Inventors: 曹路; 宋凤麒; 刘翊; 张同庆
Original assignee: Jiangsu Jichuang Atomic Cluster Technology Research Institute Co ltd
Current assignee: Jiangsu Jichuang Atomic Cluster Technology Research Institute Co ltd
Priority date: 2021-04-25
Filing date: 2021-04-25
Publication date: 2021-07-30

Abstract

A method of forming a low-temperature silicide film on a substrate supplies a raw material gas to a cluster forming chamber to form a gas cluster; moving the gas clusters to an ionization acceleration chamber to form a gas cluster ion beam GCIB; injecting a GCIB into a processing chamber, the processing chamber containing a substrate; injecting a precursor gas into the processing chamber through an injection device, wherein the injection device is positioned on top of the processing chamber in a manner such that the precursor gas reaches a localized area of the substrate; and forming a silicide film on the substrate by bombarding the substrate with GCIB in the presence of the precursor gas; injecting the GCIB into the processing chamber is performed through an aperture located between the ionization acceleration chamber and the processing chamber to form a collimated GCIB.

Description

Method for growing anisotropic film and gas cluster reactor

Technical Field

The present invention relates to semiconductor manufacturing, and more particularly to a method and apparatus for growing low temperature silicide films, particularly gas cluster reactors.

Background

Complementary Metal Oxide Semiconductor (CMOS) technology is commonly used to fabricate Field Effect Transistors (FETs) as part of advanced Integrated Circuits (ICs) such as CPUs, memories, memory devices, and the like. Perhaps the most common of which is a Metal Oxide Semiconductor Field Effect Transistor (MOSFET). In a typical MOSFET, the gate structure may be energized to generate an electric field in the underlying channel region of the substrate by which charge carriers are allowed to travel through the channel region between the source and drain regions. As IC dimensions continue to shrink, it is contemplated that high carrier mobility materials may be used in the channel region to improve device performance at the 14nm node and beyond. Group III-V materials, such as gallium arsenide (GaAs) and indium gallium arsenide (InGaAs), may be potential materials to replace silicon (Si).

Disclosure of Invention

The ability to perform low temperature silicide film growth and in situ preclean of the substrate may be helpful in implementing a new generation of group III-V channel materials in current CMOS technology.

A method of forming a low temperature silicide film on a substrate may include supplying a source gas to a cluster formation chamber to form gas clusters, which may be moved to an ionization acceleration chamber to form a Gas Cluster Ion Beam (GCIB). A GCIB can be injected into a processing chamber containing a substrate. A precursor gas may be injected into the processing chamber by an injection device to form a silicide film on the substrate by bombarding the substrate with GCIB in the presence of the precursor gas.

A method of performing in-situ cleaning of a substrate may include supplying an etchant gas to a cluster formation chamber to form gas clusters, which may then be moved to an ionization acceleration chamber to form a Gas Cluster Ion Beam (GCIB). A GCIB can be implanted into a processing chamber containing a substrate and bombarded with the GCIB to remove contaminants on the substrate.

A Gas Cluster Ion Beam (GCIB) apparatus may include a source gas cluster formation chamber, an ionization acceleration chamber coupled to the cluster formation chamber, a processing chamber coupled to the ionization acceleration chamber, a portion of a processing portion of a precursor gas injection apparatus located on top such that a precursor gas is directed to a surface of a substrate contained in the processing chamber, and an opening between the ionization acceleration chamber and the processing chamber.

Drawings

Fig. 1 is a sectional view of a Gas Cluster Ion Beam (GCIB) apparatus according to an embodiment of the present invention.

Figure 2 is a cross-sectional view of a GCIB apparatus depicting the formation of a gas cluster ion beam and the implantation of precursor gases to form a silicide film on a substrate in accordance with an embodiment of the present invention;

figure 3 is a cross-sectional view of a GCIB apparatus depicting the formation of a broad gas cluster ion beam and the implantation of precursor gases to form a silicide film on a substrate, in accordance with an alternative embodiment of the present invention.

The drawings are not necessarily to scale. The drawings are merely schematic representations, not intended to portray specific parameters of the invention. The drawings are intended to depict only typical embodiments of the invention. In the drawings, like numbering represents like elements.

Detailed Description

The invention is described in detail below with reference to the figures and examples.

Detailed embodiments of the claimed structures and methods are disclosed herein. However, it is to be understood that the disclosed embodiments are merely illustrative of the claimed structures and methods that may be embodied in various forms. This invention may, however, be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. Rather, these exemplary embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

In the following description, numerous specific details are set forth, such as specific structures, components, materials, dimensions, processing steps and techniques, in order to provide a thorough understanding of the present invention. However, it will be appreciated by one of ordinary skill in the art that the invention may be practiced without these specific details. In other instances, well-known structures or processing steps have not been described in detail in order to avoid obscuring the invention. It will be understood that when an element as a layer, region or substrate is referred to as being "on" or "over" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "directly on" or "directly on" another element, there are no intervening elements present. It will also be understood that when an element is referred to as being "under," "beneath," or "beneath" another element, it can be directly under or beneath the other element or intervening elements may be present. In contrast, when an element is referred to as being "directly below" or "directly under" another element, there are no intervening elements present.

In the following detailed description, some process steps or operations known in the art may be combined together for presentation and for illustrative purposes, and in some cases may not be described in detail, in order not to obscure the presentation of embodiments of the present invention. In other cases, some process steps or operations known in the art may not be described at all. It should be understood that the following description focuses rather on unique features or elements of various embodiments of the present invention.

As the semiconductor industry continues to shrink device dimensions, new generations of high carrier mobility channel materials have been considered to further improve device performance. Group III-V materials such as GaAs and InGaAs may be potential candidates for replacing Si as a channel material. However, fabricating low resistance contacts on source and drain regions formed with these III-V materials can present challenges to their implementation. One possible challenge may include forming low resistance silicides on complex materials, such as InGaAs. In this case, the physical properties of the III-V material may require a deposition temperature of less than 400 ℃ in forming the silicide, which in turn may limit the choice of silicide material. Thus, forming a silicide contact in the SEL arrangement using conventional methods (including metal film deposition and high temperature annealing) may not be compatible with silicide film growth on III-V materials.

Current techniques such as Gas Cluster Ion Beam (GCIB) processes may exhibit unique nonlinear effects that may be valuable for surface processing applications, particularly the formation of low temperature silicide films. By adding an implantation device to the processing chamber of a GCIB device, embodiments of the present disclosure can, among other potential benefits, also perform low temperature anisotropic deposition, such that highly conductive silicide films can be grown directly on the surface of the III-V material family. Such low temperature anisotropic deposition can reduce the contact resistance of the silicide and potentially improve device performance.

The present invention relates generally to semiconductor manufacturing and more particularly to the growth of low temperature silicide films. Low temperature silicide film deposition can be performed by modifying the GCIB device. One method of modifying a GCIB device for low temperature silicide film growth may include adding an injection device to a processing chamber of the GCIB device. One embodiment of forming a silicide film on a surface of a III-V material using a modified GCIB device is described in detail below with reference to fig. 1-2.

Reference is now made to the figures. Referring to fig. 1, a Gas Cluster Ion Beam (GCIB) apparatus 100 is shown in accordance with an embodiment of the present disclosure. In the depicted embodiment, GCIB apparatus 100 can include cluster formation chamber 102, ionization acceleration chamber 108, and processing chamber 110, in which a substrate or substrate 126 can be placed for processing. The aperture 114 may control the size of the subsequently formed gas cluster ion beam. The aperture 114 may have a width that is capable of producing a collimated gas cluster ion beam as shown in fig. 1.

The GCIB apparatus 100 can be configured to generate a gas cluster ion beam suitable for processing a substrate 126. In the depicted embodiment, the substrate 126 may comprise a semiconductor wafer made of any of several known semiconductor materials, including but not limited to silicon, germanium, silicon-germanium alloys, carbon-doped silicon-germanium alloys, and compound (e.g., group III-V and group II-VI) semiconductor materials. Non-limiting examples of compound semiconductor materials include GaAs, InAs, and/or InGaAs. In an exemplary embodiment, the substrate 126 may comprise GaAs.

The GCIB apparatus 100 can also include an implantation apparatus 120 located on the top of the processing chamber 110. The injection device 120 may be positioned relative to the substrate 126. More specifically, the position of the injection device 120 may allow for directional injection. The subsequently injected precursor gases are used for local processing of the substrate 126. In one embodiment, the implant device may be positioned at an angle of about 45 ° relative to the plane of the substrate 126. It should be noted, however, that the implantation device may be positioned 120 at any tilt angle that allows for local processing of a region of the substrate 126. The injection means 120 may comprise, for example, a showerhead arrangement having a plurality of openings through which the precursor gases may flow.

Referring to fig. 2, a source gas 204 may be supplied to the cluster forming chamber 102 to form a gas cluster beam (not shown), which may then be ionized and accelerated in the ionization acceleration chamber 108 to form a gas cluster ion beam 208 (hereinafter referred to as "gas clusters"). The GCIB208 may be used to form a silicide film 230 on the substrate 126 housed in the processing chamber 110.

The processing steps involved in the formation of GCIB208 are well known to those skilled in the art and may include forming gas-clusters in cluster forming chamber 102 by expanding feedstock gas 204 through a room temperature nozzle (not at high pressure) at room temperature. As shown). The gas-clusters may then enter an ionization acceleration chamber 108 located downstream of the cluster forming chamber 102. Once in the ionization acceleration chamber 108, a second vacuum phase can occur, in which the gas clusters can be ionized by electron bombardment and then accelerated to a high potential from about 1keV to about 100 keV. The energy range of the GCIB208 can vary depending on the intended use of the GCIB apparatus 100. For the purpose of silicide film growth, the GCIB208 may have an energy range from about 10keV to about 60 keV.

In some embodiments, magnetic filtration of the GCIB208 may be performed prior to performing a subsequent vacuum phase in the processing chamber 110 in order to reduce monomer ion contamination. The resulting beam may include cluster ions having a size distribution that may range from a few hundred atoms to several thousand atoms. In one embodiment, the size distribution of GCIB208 may vary from about 100 atoms/cluster to about 20,000 atoms/cluster. In another embodiment, the size distribution of GCIB208 can vary from about 5,000 atoms/cluster to about 10,000 atoms/cluster.

At this point, a neutralizer assembly (not shown) coupled to the processing chamber 110 may inject low energy electrons into the GCIB208 to reduce space charge explosion and avoid charge accumulation on non-conductive substrates. As the GCIB208 enters the processing chamber 110, mechanical scanning may be used to uniformly process the substrate 126. In some embodiments, a faraday current monitor (not shown) may be used for dose control of GCIB 208. The GCIB208 can range from about 1e¹²Clusters/cm²To about 1e¹⁸Clusters/cm²。

Depending on the application, the gas clusters may be generated from a variety of gases. For purposes of silicide film growth, source gas 204 may comprise any metal or silicon-containing gas suitable for silicide formation. In one embodiment, source gas 204 may include a silicon source gas, such as SiH₂Cl₂(DCS)，Si₂H₆，SiCl₄And SiHCl₃. In another embodiment, source gas 204 may comprise a metal source gas, such as TiCl₄，WF₆And metallizations, including cobalt and nickel-based compounds.

Reference is continued to the figures. Referring to fig. 2, a precursor gas 210 may be introduced into the process chamber 110 through the injector 120. The precursor gas 210 may be directionally injected so as to reach the surface of the substrate 126. The precursor gas 210 may include any metal or silicon containing gas. Gases suitable for silicide formation. In one embodiment, precursor gas 210 may include a silicon source gas, such as SiH₂Cl₂(DCS)，Si₂H₆，SiCl₄And SiHCl₃. In another embodiment, the precursor gas 210 may comprise a metal source gas, such as TiCl₄，WF₆And metallizations, including cobalt and nickel-based compounds.

It should be understood that if source gas 204 comprises a silicon source gas, precursor gas 210 may comprise a metal source gas and vice versa.

In one embodiment, the precursor gas 210 and the GCIB208 may be injected into the processing chamber 110 simultaneously to process the substrate 126. In this embodiment, simultaneous cluster ion bombardment and precursor gas exposure may occur on the substrate 126, and atomic attachment of high energy cluster ions, which may initiate a chemical reaction at the substrate surface to promote the growth of the silicide film 230, may primarily promote the generation of precursor gas 210 (or molecules) on the substrate 126. Thus, the growth rate 230 of the silicide film can be controlled by the GCIB208 flux.

It should be noted that in embodiments in which precursor gas 210 and GCIB208 may be injected into processing chamber 110 simultaneously, precursor gas 210 and GCIB208 may collide before reaching substrate 126. These collisions may result in gas-clusters. Energy is lost before reaching the substrate 126, which may affect the deposition process. To reduce collisions between precursor gas 210 and GCIB208, the pressure in processing chamber 110 may be kept low enough to minimize collisions. For example, the pressure in the process chamber 110 may be maintained at from about 10^-6Is held to about 10^-2Within the range of torr to minimize collisions between the precursor gas 210 and the GCIB208 prior to reaching the substrate 126.

In another embodiment, precursor gas 210 may be introduced into processing chamber 110 during a cycle of precursor gas injection followed by GCIB injection, or vice versa. In other words, a cyclical deposition may be performed in which an implant pulse of precursor gas 210 is followed by GCIB208 to form silicide film 230 on substrate 126. It should be noted that the growth of silicide film 230 may be performed layer by layer. In this embodiment, one or more monolayers of precursor material on the substrate surface can react with incoming energetic gas cluster ions, which can result in the growth of silicide film 230. The thickness of silicide film 230 may be controlled by controlling the number of pulses of precursor gas 210 and GCIB 208.

Processing chamber 110 can further include a mechanical scanning system that can allow substrate 126 to move in different directions so that GCIB208 and precursor gas 210 can reach the entire surface of substrate 126. As a result, a film 230 of silicide having a substantially uniform thickness may be formed on the substrate 126.

It should be understood that the terms "growth and/or deposition" and "forming and/or growth" refer to the growth of material on a deposition surface, such as substrate 126.

The GCIB208, together with the precursor gases 210 injected into the processing chamber 110 by the injector 120, may provide a low temperature thin film deposition process that may facilitate the formation of a silicide film on the substrate 126 at an enhanced density. Silicide films deposited by conventional deposition techniques may not exhibit adhesion, smoothness, crystallinity, and electrical properties. Moreover, because the GCIB process is anisotropic, the silicide film may be deposited substantially on the surface perpendicular to the direction of GCIB208, thereby having minimal impact on the surface of substrate 126 parallel to GCIB 208.

In another embodiment, GCIB208 may be used to pre-clean substrate 126 in-situ prior to forming silicide film 230. The preclean of substrate 126 may remove contaminants and create a uniform substrate surface, which may be beneficial for further processing steps, including the formation of silicide film 230. In this embodiment, source gas 204 may comprise any suitable etchant gas, such as NF₃。

Another embodiment of modifying a GCIB device for low temperature silicide film growth on III-V materials is described in detail below with reference to fig. 3. The present embodiments may include modifying the aperture of the processing chamber and adding an injection device to the processing chamber of the GCIB device.

Referring now to FIG. 3, a wide GCIB 320 may be formed in a GCIB apparatus 300 according to an alternative embodiment of the present disclosure. In this embodiment, aperture 114 (FIG. 2) can be modified so that it has a width that increases the cluster distribution size to form a wide GCIB 320. By doing so, a significantly larger area can be achieved for a wide GCIB 320. The substrate 126 is larger than the GCIB208 (fig. 2). In one embodiment, the aperture 114 (FIG. 2) may remain in place, but may widen to form a wide GCIB (FIG. 2). In the depicted embodiment, the holes 114 (FIG. 2) can be completely removed to form a wide GCIB 320, which can bombard the entire surface of the substrate 126. In embodiments where a wide GCIB 320 can be formed, mechanically scanning the substrate 126 may not require reaching a uniform processing of the substrate 126. It should be appreciated that wide GCIB 320 may be formed from source gases similar to source gases 204 described above with reference to fig. 2.

In addition, different pressure and nozzle size combinations may be required to increase the strength of the broad GCIB 320 and achieve larger distribution sizes. In one embodiment, the broad GCIB 320 size distribution can vary from about 100 atoms/cluster to about 20,000 atoms/cluster. In another embodiment, the size distribution of GCIB 320 can vary from about 5,000 atoms/cluster to about 10,000 atoms/cluster.

In the depicted embodiment, wide GCIB 320 can include an energy range varying from about 10keV to about 60keV, and can be at about 1e¹²Clusters/cm²To about 1e¹⁸Clusters/cm²The dose implantation of (2).

An injector 340 may be added to the process chamber 110. As shown in fig. 1, the injector 340 may be located at the top of the process chamber 110. The injection device 340 may be positioned relative to the substrate 126. However, unlike the injection device 120 (fig. 1), the injection device 340 may be different from the injection device 120 (fig. 1). Directional injection of subsequently inserted precursor gases 360 to process the substrate 126 is not necessarily permitted.

Next, a precursor gas 360 may be introduced into the process chamber 110 through the injector 340. Precursor gas 360 may include any metal-containing or silicon-containing gas suitable for forming a silicide. In one embodiment, precursor gas 360 may include a silicon source gas, such as SiH₂Cl₂(DCS)，Si₂H₆，SiCl₄Or SiHCl₃. In another embodiment, the precursor gas 360 may comprise a metal source gas, such as TiCl₄，WF₆And metallizations, including cobalt and nickel-based compounds.

In one embodiment, precursor gas 360 and wide GCIB 320 may be injected simultaneously into processing chamber 110 to process substrate 126. In another embodiment, the precursor gas 360 may be introduced into the process chamber 110 in cycles of precursor gas. Injections were followed by GCIB injections and vice versa.

In embodiments where precursor gas 360 and coarse GCIB 320 may be injected into processing chamber 110 simultaneously, precursor gas 360 may be injected until a pressure is reached at which the wide GCIB 320 and precursor gas 360 may collide. Since collisions may cause the gas-clusters to lose energy before reaching substrate 126, the pressure in processing chamber 110 may be kept low enough so that collisions between precursor gas 360 and wide GCIB 320 may be reduced. For example, in one embodiment, the pressure in the process chamber 110 may be maintained at from about 10^-2Is held to about 10^-1In order to minimize collisions between the precursor gas 360 and the wide GCIB 320. To the substrate 126.

In another embodiment, a wide GCIB 320 may be used to pre-clean the substrate 126 in-situ prior to forming the silicide film 380. The precleaning of the substrate 126 may remove contaminants and create a uniform substrate surface that may facilitate further processing steps, including the formation of the silicide film 380. In this embodiment, source gas 204 may comprise any suitable etchant gas, such as NF₃。

Thus, by adding an implantation device into the processing chamber of a GIBC device, low temperature silicide growth can be performed to form a highly conductive silicide film on a substrate that can include III-V materials. As a result, resistance may be reduced, thereby enhancing device performance and potentially increasing product yield and reliability. In addition, the substrate may be pre-cleaned in-situ prior to deposition of the silicide film to improve surface conditions.

The description of various embodiments of the present invention has been presented for purposes of illustration but is not intended to be exhaustive or limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles of the embodiments, the practical application or technical improvements to the technology found in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A method for forming a low-temperature silicide film on a substrate is characterized by comprising the following steps:

supplying a raw material gas to a cluster forming chamber to form a gas cluster;

moving the gas clusters to an ionization acceleration chamber to form a gas cluster ion beam GCIB;

injecting a GCIB into a processing chamber, the processing chamber containing a substrate;

injecting a precursor gas into the processing chamber through an injection device, wherein the injection device is positioned on top of the processing chamber in a manner such that the precursor gas reaches a localized area of the substrate; and forming a silicide film on the substrate by bombarding the substrate with GCIB in the presence of the precursor gas; injecting the GCIB into the processing chamber is performed through an aperture located between the ionization acceleration chamber and the processing chamber to form a collimated GCIB.

2. The method of claim 1, wherein the holes are widened or removed to form a wide GCIB.

3. The method of claim 2, wherein the wide GCIB substantially bombards the surface of the substrate.

4. The method of claim 1, wherein the combination of the source gas and the precursor gas comprises a silicon source gas and a metal source gas to form a silicide film on the substrate.

5. The method of claim 4, wherein the silicon source gas comprises SiH₂Cl₂(DCS)，Si₂H₆，SiCl₄Or SiHCl₃。

6. The method as set forth in claim 4,wherein the metal source gas comprises TiCl₄，WF₆Or a metal alpha acid salt.

7. The method of claim 1, wherein the substrate comprises a group III-V material, such as GaAs and InGaAs.

8. The method of claim 1, wherein the injection device comprises a device having a plurality of openings through which the precursor gas flows.

9. The method of claim 1, wherein injecting the GCIB into the processing chamber and injecting the precursor gas into the processing chamber through the injection device are performed simultaneously to cause a chemical reaction on the surface of the substrate to promote growth of the substrate. The rate of the silicide film is controlled by the GCIB flux.

10. The method of claim 1, wherein injecting the GCIB into the process chamber and injecting the precursor gas into the process chamber through the injector are performed in one or more cycles of precursor gas injection followed by GCIB injection and vice versa. A monolayer of precursor gas reacts with the incoming GCIB on the substrate surface, resulting in the growth of a silicide film, the thickness of which is controlled by the amount of precursor gas and the GCIB pulse; the pressure in the processing chamber is maintained at about 10-6 torr to 10-2 torr to reduce the number of collisions between the precursor gas and the GCIB.