KR20210088771A - High Growth Rate Deposition for Group III/V Materials - Google Patents

Abstract

Aspects of the present invention provide high rates, such as at least about 30 μm/hr, e.g., about 40 μm/hr, about 50 μm/hr, about 55 μm/hr, about 60 μm/hr, about 70 μm/hr. , about 80 μm/hr, and about 90-120 μm/hr deposition rates for epitaxial growth of group III/V materials. The group III/V materials or films may be used in solar thermal, semiconductor, or other electronic device applications. Group III/V materials may be formed or grown on a sacrificial layer disposed over or on a support substrate during a vapor deposition process. The group III/V material may then be removed from the support substrate during an epitaxial lift off (ELO) process. Group III/V materials include gallium arsenide, gallium aluminum arsenide, gallium indium arsenide, gallium indium arsenide nitride, gallium aluminum indium phosphide, phosphide thereof, nitride thereof, derivatives thereof, A thin film of an epitaxially grown layer containing an alloy, or a combination thereof.

Description

High Growth Rate Deposition for Group III/V Materials

Cross-referencing of related applications

This application claims priority to U.S. Regular Patent Application No. 15/717,694 "HIGH GROWTH RATE DEPOSITION FOR III/V MATERIALS," filed on September 27, 2017, which is incorporated herein by reference. U.S. Application No. 15/717,694 is 12/ of a regular patent application filed on October 13, 2010, claiming the benefit of Provisional Patent Application No. 61/251,677, filed on October 14, 2009 under 35 USC 119(e) 904,090 is a continuation application in part. Each of these is incorporated herein by reference in its entirety.

field of invention

Embodiments of the present invention relate generally to processes for solar, semiconductor, or other electronic device applications, and more specifically to epitaxial growth of Group III/V materials.

Description of related technology

Group III/V materials, such as gallium arsenide or gallium aluminum arsine, may be deposited or formed by epitaxial growth during a chemical vapor deposition (CVD) process. However, epitaxial growth of high-quality group III/V materials is often quite slow. A typical CVD process can epitaxially grow a group III/V material at a deposition rate of about 1 μm/hr to about 3 μm/hr. By slightly increasing the deposition rate, the quality of the epitaxial material is generally greatly reduced. Group III/V materials, which usually grow at deposition rates of about 5 μm/hr, are of poor quality, often have structural defects within the crystal lattice, or contain amorphous materials.

There is therefore a need for a deposition process for depositing high quality, epitaxial Group III/V materials at high growth rates (eg, growth rates exceeding at least 5 μm/hr).

Embodiments of the present invention generally have high growth rates or deposition rates, such as about 30 μm/hr or greater, such as about 40 μm/hr, about 50 μm/hr, about 55 μm/hr, about 60 μm. /hr, about 70 μm/hr, about 80 μm/hr, or about 90-120 μm/hr, related to a process for epitaxially growing a group III/V material. As used herein, the term “greater” with respect to a growth or deposition rate may refer to a higher deposition rate, including those described within the context of the present invention. As used herein, the term “about” refers to an approximate value that may be within ±1%, ±2%, ±3%, ±5%, ±10%, ±15%, or ±20% of the nominal value. can do. Additionally, as used herein, the range 90-120 μm/hr includes one or more different growth or deposition rates, such as about 90 μm/hr, about 95 μm/hr, about 100 μm/hr, about 105 μm/hr, about 110 μm/hr, about 115 μm/hr, or about 120 μm/hr. The deposited Group III/V material or film may be used in solar, semiconductor, or other electronic device applications. In some embodiments, group III/V materials may be formed or grown on a sacrificial layer disposed over or on a support substrate during a vapor deposition process. The group III/V material may then be removed from the support substrate during an epitaxial lift off (ELO) process. Group III/V materials include gallium arsenide, gallium aluminum arsenide, gallium indium arsenide, gallium indium arsenide nitride, gallium aluminum indium phosphide, phosphide thereof, nitride thereof, derivatives thereof, A thin film of an epitaxially grown layer containing an alloy, or a combination thereof. Group III/V materials may also be referred to as group III/V semiconductors or group III/V semiconductor materials.

In one embodiment, a method is provided for forming a group III/V material containing gallium arsenide on a wafer, the method comprising heating the wafer to a deposition temperature of at least about 600° C. in a process system. , exposing the wafer to a deposition gas containing a gallium precursor gas and arsine, and depositing a layer of gallium arsenide on the wafer at a deposition rate of at least about 30 μm/hr. As used herein, the term “at least 30 μm/hr” refers to, for example, about 40 μm/hr, about 50 μm/hr, about 55 μm/hr, about 60 μm/hr, about 70 μm/hr, growth or deposition rates of about 80 μm/hr, or about 90-120 μm/hr. Additionally, as used herein, the term “greater” may refer to a higher temperature, including those described within the context of the present invention with respect to deposition temperature. In another embodiment, the wafer is heated in a process system to a deposition temperature of at least about 650° C. and exposed to a deposition gas containing gallium precursor gas, aluminum precursor gas and arsine. A layer of gallium aluminum arsenide containing group III/V material is grown at a deposition rate of at least about 30 μm/hr. For 90-120 μm/hr deposition rates, the deposition temperature may range from about 680°C to about 850°C.

In another embodiment, the method includes heating the wafer to a deposition temperature of at least about 600° C. in a process system, exposing the wafer to a deposition gas containing gallium precursor gas, indium precursor gas, and arsine, and about depositing a group III/V layer or material on the wafer at 30 μm/hr or greater (eg, 90-120 μm/hr deposition rate). Group III/V layers or materials contain gallium, arsenic and indium. In one example, the deposition temperature is from about 650°C to about 800°C. In some examples, the gallium precursor gas contains trimethylgallium and the indium precursor gas contains trimethylindium. For 90-120 μm/hr deposition rates, the deposition temperature may range from 680°C to about 850°C.

In some embodiments, the deposition rate or growth rate is at least about 40 μm/hr, such as at least about 50 μm/hr, preferably at least about 55 μm/hr, more preferably at least about 60 μm/hr ( for example, 90-120 μm/hr deposition rate). In still other embodiments, the deposition temperature may be at least about 600°C, at least about 700°C, at least about 800°C, or at least about 850°C. In some examples, the deposition temperature may be in the range of about 550°C to about 900°C. In another example, the deposition temperature may be from about 600°C to about 800°C. In another example, the deposition temperature may be from about 650°C to about 750°C. In another DP time, the deposition temperature may be from about 650°C to about 720°C. For 90-120 μm/hr deposition rates, the deposition temperature may range from about 680°C to about 850°C.

In another embodiment, a method includes heating the wafer to a deposition temperature of at least about 600° C. in a process system, exposing the wafer to a deposition gas containing gallium precursor gas, indium precursor gas, nitrogen precursor gas, and arsine. depositing a Group III/V layer or material onto the wafer at a deposition rate of at least about 30 μm/hr (eg, 90-120 μm/hr deposition rate), wherein the Group III/V layer or material comprises: It contains gallium, arsenic, indium, and nitrogen. The nitrogen precursor gas may contain hydrazine, methylhydrazine, dimethylhydrazine, derivatives thereof, or combinations thereof. In one example, the nitrogen precursor gas contains dimethylhydrazine. In another example, the nitrogen precursor gas contains hydrazine. In some examples, the gallium precursor gas contains trimethylgallium and the indium precursor gas contains trimethylindium. The deposition temperature may range from about 680°C to about 850°C for a 90-120 μm/hr deposition rate.

In another embodiment, a method includes heating a wafer to a deposition temperature of at least about 600° C. in a process system, exposing the wafer to a deposition gas containing a gallium precursor gas, an indium precursor gas, an aluminum precursor, and a phosphorus precursor; , depositing a Group III/V layer or material on the wafer at a deposition rate of at least about 30 μm/hr (eg, 90-120 μm/hr deposition rate), wherein the Group III/V layer or material is gallium , indium, aluminum, and phosphorus. In one example, the gallium precursor contains trimethylgallium, the aluminum precursor contains trimethylaluminum, the indium precursor contains trimethylindium, and the phosphorus precursor contains phosphine. For 90-120 μm/hr deposition rates, the deposition temperature may range from about 680°C to about 850°C.

In order that the stated features of the invention may be understood in detail, a more specific description of the invention, briefly summarized above, is provided with reference to embodiments, some of which are illustrated in the accompanying drawings. However, the accompanying drawings show only general embodiments of the present invention, and therefore are not considered to be limiting of the scope of the present invention, and other equivalent effective embodiments may be admitted.
1 depicts an illustration of a gallium arsenide stack comprising various Group III/V layers, described by some embodiments described herein.
2 depicts an example of a method for forming a semiconductor material on a wafer, described in some embodiments.
3 shows an example of another method for forming a semiconductor material on a wafer, described in some embodiments.
4 shows an illustration of another method for forming a semiconductor material on a wafer, described in some embodiments.
5 depicts an illustration of a method for forming a cell, described in some embodiments.

The following description is presented to enable any person skilled in the art to make and use the present invention and is provided in the context of a patent application and its requirements. Various modifications to the preferred embodiments and general principles and features described herein will be readily apparent to those skilled in the art. Accordingly, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features described herein.

Embodiments of the present invention generally provide high growth rates, such as about 30 μm/hr or greater, such as about 40 μm/hr, about 50 μm/hr, about 55 μm/hr, about 60 μm/hr, about Processes for epitaxially growing Group III/V materials at 70 μm/hr, about 80 μm/hr, or about 90-120 μm/hr. The deposited Group III/V material or film may be used in solar, semiconductor, or other electronic device applications. These electronic device applications may include applications involving optoelectronic devices, components or modules. In some embodiments, group III/V materials may be formed or grown on a sacrificial layer disposed over a support substrate during a vapor deposition process. The group III/V material may then be removed from the support substrate, for example, during an epitaxial lift off (ELO) process. Group III/V materials include gallium arsenide, gallium aluminum arsenide, gallium indium arsenide, gallium indium arsenide nitride, gallium aluminum indium phosphide, phosphides thereof, nitrides thereof, derivatives thereof , a thin film of an epitaxially grown layer containing an alloy thereof, or a combination thereof.

In one embodiment, a method is provided for forming a group III/V material containing gallium arsenide on a wafer, the method comprising: heating the wafer to a deposition temperature of at least about 550° C. in a processing system; exposing the wafer to a deposition gas containing a gallium precursor gas and arsine, and depositing a layer of gallium arsenide on the wafer at a deposition rate of at least about 30 μm/hr.

In another embodiment, a method is provided for forming a group III/V material containing gallium aluminum arsenide, the method comprising: heating the wafer to a deposition temperature of at least about 650° C. in a processing system; exposing to a deposition gas containing a gallium precursor gas, an aluminum precursor gas, and arsine, and depositing a layer of gallium aluminum arsenide at a deposition rate of at least about 30 μm/hr. In one example, the group III/V material contains an n-type gallium aluminum arsenide layer having the formula _{Al 0.3} Ga _{0.7 As.}

In another embodiment, a method is provided for forming a group III/V material on a wafer or substrate, the method comprising: heating the wafer to a deposition temperature of at least about 600° C. in a processing system; , an indium precursor gas, and a deposition gas containing arsine, and depositing a group III/V layer on the wafer at a deposition rate of at least about 30 μm/hr. Group III/V layers contain gallium, arsenic and indium. In one example, the deposition temperature is in the range of about 650°C to about 800°C. In some examples, the gallium precursor gas contains trimethylgallium and the indium precursor gas contains trimethylindium.

In another embodiment, a method is provided for forming a group III/V material on a wafer or substrate, the method comprising: heating the wafer to a deposition temperature of at least about 600° C. in a processing system; , exposing to a deposition gas comprising an indium precursor gas, a nitrogen precursor gas, and arsine, depositing a group III/V layer on the wafer at a deposition rate of at least about 30 μm/hr, the III/V The group layer contains gallium, arsenic, indium, and nitrogen. The nitrogen precursor gas may contain hydrazine, methylhydrazine, dimethylhydrazine, derivatives thereof, or combinations thereof. In one example, the nitrogen precursor gas contains dimethylhydrazine. In another example, the nitrogen precursor gas contains hydrazine. In some examples, the gallium precursor gas contains trimethylgallium and the indium precursor gas contains trimethylindium.

In yet another embodiment, a method is provided for forming a group III/V material on a wafer or substrate, the method comprising heating the wafer to a deposition temperature of at least about 600° C. in a processing system; A method comprising: exposing to a deposition gas containing a gas, an indium precursor gas, an aluminum precursor, and a phosphorus precursor, depositing a group III/V layer on the wafer at a deposition rate of at least about 30 μm/hr; The group layer contains gallium, indium, aluminum, and phosphorus. In one example, the gallium precursor contains trimethylgallium, the aluminum precursor contains trimethylaluminum, the indium precursor contains trimethylindium, and the phosphorus precursor contains phosphine.

In some embodiments, the deposition rate or growth rate is at least about 40 μm/hr, such as at least about 50 μm/hr, preferably at least about 55 μm/hr, more preferably at least about 60 μm/hr (such as , about 70 μm/hr, about 80 μm/hr, or about 90-120 μm/hr). In still other embodiments, the deposition temperature may be at least about 600°C, at least about 700°C, at least about 800°C, or at least about 850°C. In some examples, the deposition temperature may be from about 550°C to about 900°C. In another example, the deposition temperature may be from about 600°C to about 800°C. In another example, the deposition temperature may be from about 650°C to about 750°C. In another example, the temperature may be from about 650°C to about 720°C. In another example, for example, for a deposition rate of about 90-120 μm/hr, the deposition temperature may be between about 680° C. and about 850° C.

The gallium precursor gas may contain an alkyl gallium compound. In one example, the alkyl gallium compound may be trimethylgallium or triethylgallium. In some embodiments, the deposition gas may further contain an aluminum precursor gas and the gallium arsenide layer further contains aluminum. The aluminum precursor gas may contain an alkyl aluminum compound such as trimethyl aluminum or triethylaluminum. In another embodiment, the deposition gas may contain arsine and gallium precursor gas in an arsine/gallium precursor ratio of about 3 or greater, or about 4 or greater, or about 5 or greater, or about 6 or greater, or about 7 or greater. In some examples, the arsine/gallium precursor ratio can be from about 5 to about 10. In another embodiment, the Group III/V material is to be formed or grown from a deposition gas having a ratio of Group V precursor to Group III precursor of at least about 30:1, or 40:1, or 50:1, or 60:1. can In some examples, the deposition gas has about 50:1 phosphine/group III precursor.

The process system may have a withstand pressure of about 20 Torr to about 1,000 Torr. In some embodiments, the withstand pressure may be above atmospheric pressure, such as from about 760 Torr to about 1,000 Torr. In some examples, the withstand pressure may be about 800 Torr to about 1,000 Torr. In another example, the withstand pressure is between about 780 Torr and about 900 Torr, such as between about 800 Torr and about 850 Torr. In another embodiment, the withstand pressure may be below atmospheric pressure, from about 20 Torr to about 760 Torr, preferably from about 50 Torr to about 450 Torr, more preferably from about 100 Torr to about 250 Torr.

In some embodiments, the deposition gas further contains a carrier gas. The carrier gas may contain hydrogen (H ₂ ), nitrogen (N ₂ ), a mixture of hydrogen and nitrogen, argon, helium, or combinations thereof. In many instances, the carrier gas contains hydrogen, nitrogen, or a mixture of hydrogen and nitrogen.

In general, flow rates for the various gases used in the deposition process may vary depending on the chemical vapor deposition (eg, metal-organic chemical vapor deposition, ie, MOCVD) tool used for the process.

1 illustrates a gallium arsenide stack 100 containing a plurality of Group III/V materials or layers that may be formed by a high growth rate deposition process in accordance with embodiments described herein. For example, one or more of Group III/V materials or layers may be grown or deposited at any of the following deposition rates: about 30 μm/hr, about 40 μm/hr, about 50 μm/hr, about 55 μm/hr, about 60 μm/hr, about 70 μm/hr, about 80 μm/hr, about 90 μm/hr, about 95 μm/hr, about 100 μm/hr, about 105 μm/hr, about 110 μm/hr hr, about 115 μm/hr, and about 120 μm/hr. Some of the plurality of layers of group III/V material form gallium arsenide cells 110 in gallium arsenide stack 100 . 1 shows a gallium arsenide cell in which a gallium arsenide stack 100 is disposed on or over a sacrificial layer 116 disposed on or over a buffer layer 114 disposed on or over a wafer 112 . 110).

The wafer 112 may be a support substrate containing a group III/V material, and may be doped with various elements. In general, wafer 112 contains gallium arsenide, alloys thereof, derivatives thereof, and may be an n-doped substrate or a p-doped substrate. In many examples, wafer 112 is a gallium arsenide substrate or a gallium arsenide alloy substrate. The gallium arsenide substrate or wafer may have a coefficient of thermal expansion ^{of about 5.73x10 -6} °C ^-1.

The buffer layer 114 may be a gallium arsenide buffer layer containing gallium arsenide, an alloy thereof, a dopant thereof, or a derivative thereof. The buffer layer 114 may have a thickness of from about 100 nm to about 1000 nm, such as about 200 nm or about 300 nm.

The sacrificial layer 116 , referred to as the ELO emissive layer, may contain aluminum arsenide, an alloy thereof, a derivative thereof, or a combination thereof. The sacrificial layer 116 may have a thickness of about 20 nm or less. In some examples, the thickness of the sacrificial layer 116 is between about 1 nm and about 20 nm, such as between about 5 nm and about 20 nm, or in still other examples, between about 1 nm and about 10 nm, such as between about 4 nm and about 4 nm. about 6 nm.

The gallium arsenide cell 110 further includes an n-type gallium arsenide stack 120 disposed on or over the p-type gallium arsenide stack 130 . The n-type gallium arsenide stack 120 generally includes a plurality of layers of various n-type doped materials. In one embodiment, the n-type gallium arsenide stack 120 includes an emitter layer 126 disposed on or over a passivation layer 124 disposed on or over the contact layer 122 . . In some implementations, the n-type gallium arsenide stack 120 may have a thickness of about 200 nm to about 1,300 nm.

The contact layer 122 may be a gallium arsenide contact layer containing gallium arsenide, an alloy thereof, a dopant thereof, or a derivative thereof. In some examples, contact layer 122 contains an n-type gallium arsenide material. The contact layer 122 may have a thickness of about 5 nm to about 100 nm, such as about 10 nm or about 50 nm.

The passivation layer 124, also referred to as the front window, generally contains aluminum gallium arsenide, an alloy thereof, a derivative thereof, or a combination thereof. In many instances, passivation layer 124 contains an n-type aluminum gallium arsenide material. In one example, passivation layer 124 contains an n-type aluminum gallium arsenide material having the formula _{Al 0.3} Ga _{0.7 As.} The passivation layer 124 may have a thickness of about 5 nm to about 100 nm, such as about 10 nm or about 50 nm.

The emitter layer 126 may contain gallium arsenide, an alloy thereof, a derivative thereof, or a combination thereof. In many instances, emitter layer 126 contains an n-type gallium arsenide material. The emitter layer 126 may have a thickness of from about 100 nm to about 3000 nm. In some examples, the thickness of the emitter layer 126 is between about 100 nm and about 600 nm, such as between about 200 nm and about 400 nm, or in still other examples, between about 600 nm and about 1,200 nm, such as about 800 nm. to about 1,000 nm.

The p-type gallium arsenide layer or stack 130 generally includes a plurality of layers of various p-type doped materials. In one embodiment, the p-type gallium arsenide stack 130 includes a contact layer 136 disposed on or over the passivation layer 134 disposed on or over the absorber layer 132 . In an alternative embodiment, the absorber layer 132 is absent from the p-type gallium arsenide stack 130 . Thus, the p-type gallium arsenide stack 130 includes a contact layer 136 disposed on or over the passivation layer 134 , and the passivation layer 134 includes the n-type gallium arsenide stack ( 120), emitter layer 126, or another layer. In some implementations, the p-type gallium arsenide stack 130 can have a thickness of about 100 nm to about 3,000 nm.

The absorber layer 132 may include gallium arsenide, an alloy thereof, a derivative thereof, or a combination thereof. In many instances, the absorber layer 132 contains a p-type gallium arsenide material. In one embodiment, the absorber layer 132 may have a thickness of from about 1 nm to about 3,000 nm. In some examples, the thickness of the absorber layer 132 is from about 1 nm to about 1,000 nm, such as from about 10 nm to about 100 nm, or, in still other examples, from about 1,000 nm to about 3,000 nm, such as about 1,100 nm to about 2,000 nm. In some examples, the thickness of the absorber layer 132 is from about 100 nm to about 600 nm, such as from about 200 nm to about 400 nm, or, in still other examples, from about 600 nm to about 1,200 nm, such as from about 800 nm to It may be about 1,000 nm.

The passivation layer 134, also referred to as the rear window, generally comprises aluminum gallium arsenide, an alloy thereof, a derivative thereof, or a combination thereof. In many instances, passivation layer 134 includes a p-type aluminum gallium arsenide material. In one example, passivation layer 134 contains a p-type aluminum gallium arsenide material having the formula _{Al 0.3} Ga _{0.7 As.} The passivation layer 134 may have a thickness of about 25 nm to about 100 nm, such as about 50 nm or about 300 nm.

The contact layer 136 may be a p-type gallium arsenide contact layer containing gallium arsenide, an alloy thereof, a dopant thereof, or a derivative thereof. In some examples, contact layer 136 contains a p-type gallium arsenide material, and contact layer 136 can have a thickness of about 5 nm to about 100 nm, such as about 10 nm or about 50 nm. have.

As described herein, aspects of a deposition process for depositing or forming a Group III/V material may be performed within a process system, such as a single wafer deposition chamber, a multi-wafer deposition chamber, a static deposition chamber, or a continuous feed deposition chamber. can be carried out. One continuous feed deposition chamber that may be used to deposit or form Group III/V materials is disclosed in Applicant's U.S. Application Serial No. 12/475,131, filed May 29, 2009, which is incorporated herein by reference. titled "Methods and Apparatus for a Chemical Vapor Deposition Reactor" and U.S. Application No. 12/475,169, filed May 29, 2009 and issued U.S. Patent No. 8,602,707, entitled "Methods and Apparatus for a Chemical Vapor Deposition Reactor" Reactor").

Example

In one embodiment, the deposition gas may be formed by combining or mixing two, three, or more chemical precursors within a gas manifold prior to entering or passing through the showerhead. In another embodiment, the deposition gas may be formed by combining or mixing two, three, or more chemical precursors within the reaction zone after passing through the showerhead. The deposition gas may also contain one or more carrier gases, which may be combined or mixed with the precursor gas before or after passing through the showerhead. The carrier gas may be hydrogen, nitrogen, argon, or a combination thereof. The internal pressure of the deposition chamber may be about 250 Torr to about 450 Torr.

Example 1 GaAs: In one example, the deposition gas may be formed by combining a gallium precursor (eg, TMG) and an arsenic precursor (eg, arsine). The substrate may be heated to a deposition temperature and exposed to a deposition gas. The deposition temperature may have a wide range. In one example, the deposition temperature may be from about 600°C to about 800°C, such as from about 650°C to about 750°C or from about 650°C to about 720°C. In one example, the deposition gas may contain about _{100 cc of arsine in about 2,000 cc of hydrogen gas (H 2} ) and about 200 cc of a mixture _{of TMG/H 2} (about 10% TMG in _{H 2 ).} . Group III/V materials include gallium and arsenic and are at least about 30 μm/hr, such as at least about 40 μm/hr, preferably at least about 50 μm/hr, preferably at least about 55 μm/hr, More preferably, it can be deposited at about 60 μm/hr or higher. In one example, a deposition rate greater than about 60 μm/hr may include a deposition rate of about 70 μm/hr, about 80 μm/hr, or about 90-120 μm/hr. For a deposition rate of about 90-120 μm/hr, the deposition temperature may be between about 680° C. and about 850° C.

Example 2 GaAlAs: In another example, a deposition gas can be formed by combining a gallium precursor (eg, TMG), an aluminum precursor (eg, TMA), and an arsenic precursor (eg, arsine). The substrate may be heated to a deposition temperature and exposed to a deposition gas. The deposition temperature may have a wide range. In one example, the deposition temperature may be from about 600°C to about 800°C. In one example, the deposition gas is about 100 cc of arsine in about 2,000 cc of hydrogen gas; about 200 cc of a mixture _{of TMG/H 2} (about 10% TMG in _{H 2);} and about 200 cc of TMA/H ₂ (about 1% TMA in _{H 2 ).} Group III/V materials contain gallium, aluminum, and arsenic and contain at least about 30 μm/hr, such as at least about 40 μm/hr, preferably at least about 50 μm/hr, preferably at least about 55 μm/hr. hr or more, and more preferably, at a rate of about 60 μm/hr or more. For example, a deposition rate greater than about 60 μm/hr may include a deposition rate of about 70 μm/hr, about 80 μm/hr, or about 90-120 μm/hr. For a deposition rate of about 90-120 μm/hr, the deposition temperature may be between about 680° C. and about 850° C.

Example 3 - AlGaInP: In another example, the deposition gas is a gallium precursor (eg, TMG), an aluminum precursor (eg, TMA), an indium precursor (eg, trimethylindium-TMI), and a phosphorus precursor (eg, phosphine- PH ₃ ) can be formed by combining. The substrate may be heated to a deposition temperature and exposed to a deposition gas. The deposition temperature may have a wide range. In one example, the deposition temperature may be from about 600°C to about 800°C. In one example, the deposition gas is a mixture _{of about 200 cc of TMG/H 2} (about 10% TMG in _{H 2);} about 200 cc of TMA/H ₂ (about 1% TMA in _{H 2);} about 200 cc of TMI/H ₂ (about 1% TMI in _{H 2);} and about 100 cc of phosphine in about 2,000 cc of hydrogen gas. Group III/V materials contain gallium, aluminum, indium, and phosphorus and contain at least about 30 μm/hr, such as at least about 40 μm/hr, preferably at least about 50 μm/hr, preferably at least about 55 It can be deposited at a rate of at least about μm/hr, and more preferably, at least about 60 μm/hr. In one example, a deposition rate greater than about 60 μm/hr may include a deposition rate of about 70 μm/hr, about 80 μm/hr, or about 90-120 μm/hr. The deposition temperature may be from about 680°C to about 850°C for a deposition rate of about 90-120 μm/hr.

Example 4 GalnAs: In another example, the deposition gas may be formed by combining a gallium precursor (eg, TMG), an indium precursor (eg, trimethylindium), and an arsenic precursor (eg, arsine). The substrate may be heated to a deposition temperature and exposed to a deposition gas. The deposition temperature may have a wide range. In one example, the deposition temperature may be from about 600°C to about 800°C. In one example, the deposition gas is about 100 cc of arsine in about 2,000 cc of hydrogen gas; about 200 cc of a mixture _{of TMG/H 2} (about 10% TMG in _{H 2);} and about 200 cc of TMI/H ₂ (about 1% TMI in _{H 2).} Group III/V materials include gallium, indium and arsenic and are at least about 30 μm/hr, such as at least about 40 μm/hr, preferably at least about 50 μm/hr, preferably at least about 55 μm/hr. or more, and more preferably, at a rate of about 60 μm/hr or greater. In one example, a deposition rate greater than about 60 μm/hr may include a deposition rate of about 70 μm/hr, about 80 μm/hr, or about 90-120 μm/hr. The deposition temperature may be from about 680°C to about 850°C for a deposition rate of about 90-120 μm/hr.

Example 5 GalnAsN: In another example, the deposition gas is a gallium precursor (eg, TMG), an indium precursor (eg, trimethylindium), an arsenic precursor (eg, arsine), and a nitrogen precursor (eg, dimethylhydrazine or hydrazine) ) can be formed by combining The substrate may be heated to a deposition temperature and exposed to a deposition gas. The deposition temperature may have a wide range. For example, the deposition temperature may be from about 400°C to about 500°C, such as about 450°C. In one example, the deposition gas is about 10 cc of arsine in about 2,000 cc of hydrogen gas; about 200 cc of a TMG/H ₂ mixture (about 10% TMG in _{H 2 );} about 200 cc of TMI/H ₂ (about 1% TMI in _{H 2);} and about 100 cc of dimethylhydrazine in about 1,000 cc of hydrogen gas. Group III/V materials contain gallium, indium, aluminum, arsenic, and nitrogen and are at least about 30 μm/hr, such as at least about 40 μm/hr, preferably at least about 50 μm/hr, preferably, It can be deposited at a rate of at least about 55 μm/hr, and more preferably, at least about 60 μm/hr. In one example, a deposition rate greater than about 60 μm/hr may include a deposition rate of about 70 μm/hr, about 80 μm/hr, or about 90-120 μm/hr. The deposition temperature may be from about 680°C to about 850°C for a deposition rate of about 90-120 μm/hr.

Example 6 GalnAsP: In another embodiment, the deposition gas is a gallium precursor (eg, TMG), an indium precursor (eg, trimethylindium), an arsenic precursor (eg, arsine), and a phosphorus precursor (eg, phosphine- PH ₃ ) can be formed by combining. The substrate may be heated to a deposition temperature and exposed to a deposition gas. The deposition temperature may have a wide range. In one embodiment, the deposition temperature may be from about 600°C to about 800°C. In one example, the deposition gas is about 100 cc of arsine in about 2,000 cc of hydrogen gas; about 200 cc of a TMG/H ₂ mixture (about 10% TMG in _{H 2 );} about 200 cc of TMI/H ₂ (about 1% TMI in _{H 2);} and about 100 cc of phosphine in about 2,000 cc of hydrogen gas. Group III/V materials contain gallium, indium, arsenic, and phosphorus and contain at least about 30 μm/hr, such as at least about 40 μm/hr, preferably at least about 50 μm/hr, preferably at least about 55 It can be deposited at a rate of at least about μm/hr, and more preferably, at least about 60 μm/hr. In one example, a deposition rate greater than about 60 μm/hr may include a deposition rate of about 70 μm/hr, about 80 μm/hr, or about 90-120 μm/hr. The deposition temperature may be from about 680°C to about 850°C for a deposition rate of about 90-120 μm/hr.

In the embodiments described above, the term “cc” may refer to cubic centimeters and may correspond to a flow rate or flow unit, such as standard cubic centimeters per minute (sccm).

2 shows an illustration of a method 200 for forming a semiconductor material on a wafer, as described in some embodiments herein.

At block 210 , the method 200 includes heating the wafer to a deposition temperature of 550° C. to 900° C. in the process system.

At block 220, the method 200 includes exposing the wafer to a deposition gas comprising arsine and a gallium precursor gas at a voltage of 20 Torr to 1000 Torr.

At block 230, method 200 includes 30 μm/hr, 40 μm/hr, 50 μm/hr, 55 μm/hr, 60 μm/hr, 70 μm/hr, 80 μm/hr, and 90-120 depositing on the wafer one or more layers having gallium arsenide on the wafer at a deposition rate selected from the group consisting of μm/hr deposition rate, wherein the plurality of layers, e.g., one or more layers, form a gallium arsenide cell. do.

In aspects of method 200, the deposition temperature may range from 680°C to 850°C for 90-120 μm/hr deposition rates.

In another aspect of method 200, the deposition gas may further comprise an aluminum precursor gas and the gallium arsenide layer may further comprise aluminum. The aluminum precursor gas may include an alkyl aluminum compound. The alkyl aluminum compound may be trimethylaluminum or triethylaluminum.

In another aspect of method 200, the deposition gas may further comprise a carrier gas comprising a mixture of hydrogen and argon.

In another aspect of method 200 , an n-type portion of a gallium arsenide cell is deposited over a sacrificial layer having a thickness of 1 nm to 20 nm, wherein the sacrificial layer is disposed over the buffer layer, wherein the buffer layer is disposed on the wafer. placed above

In another aspect of method 200, the plurality of layers form an n-type gallium arsenide stack and a p-type gallium arsenide stack, wherein the n-type gallium arsenide stack is disposed on the first passivation layer. has an emitter layer disposed on or over the first passivation layer, wherein the first passivation layer is disposed on or over the first contact layer, and the p-type gallium arsenide stack is disposed on or over the second passivation layer. and a contact layer, wherein a second passivation layer is disposed on or over the absorber layer.

In another aspect of the method 200, the deposition temperature may range from 600°C to 800°C.

In another aspect of method 200, the range of voltage force may be selected from the group consisting of 20 Torr to 760 Torr, 50 Torr to 450 Torr, and 100 Torr to 250 Torr.

3 shows an illustration of a method 300 for forming a semiconductor material on a wafer, as described in some implementations herein.

At block 310 , the method 300 includes heating the wafer to a deposition temperature between 550° C. and 900° C. in the process system.

At block 320, the method 300 includes exposing the wafer to a deposition gas comprising a gallium precursor gas, an aluminum precursor gas, and arsine at a voltage force between 20 Torr and 1000 Torr.

At block 330 , method 300 includes 30 μm/hr, 40 μm/hr, 50 μm/hr, 55 μm/hr, 60 μm/hr, 70 μm/hr, 80 μm/hr, and 90-120 depositing at least one layer on the wafer at a deposition rate selected from the group consisting of μm/hr deposition rate, wherein the at least one layer comprises aluminum gallium arsenide and a plurality of layers comprising the at least one layer. A layer of gallium arsenide cells is included.

In one aspect of method 300 , the deposition temperature ranges from 680° C. to 850° C. for a 90-120 μm/hr deposition rate.

In another aspect of method 300 , an n-type portion of a gallium arsenide cell is deposited over a sacrificial layer having a thickness of 1 nm to 20 nm, the sacrificial layer disposed over the buffer layer, the buffer layer being over the wafer. are placed

In another aspect of method 300 , the plurality of layers form an n-type gallium arsenide stack and a p-type gallium arsenide stack, wherein the n-type gallium arsenide stack comprises a first passivation layer having an emitter layer disposed on or over the first passivation layer, wherein the first passivation layer is disposed on or over the first contact layer, and the p-type gallium arsenide stack is disposed on or over the second passivation layer. It has two contact layers, and a second passivation layer is disposed on or over the absorber layer.

In another aspect of method 300 , the deposition temperature may range from 600°C to 800°C.

In another aspect of method 300 , the range of voltage force may be selected from the group consisting of 20 Torr to 760 Torr, 50 Torr to 450 Torr, and 100 Torr to 250 Torr.

4 shows an illustration of a method 400 for forming a semiconductor material on a wafer, as described in some implementations herein.

At block 410 , the method 400 includes heating the wafer to a deposition temperature between 550° C. and 900° C. in the process system.

At block 420, the method 400 includes exposing the wafer to a deposition gas comprising a gallium precursor gas, an indium precursor gas, a nitrogen precursor gas, and arsine at a voltage force between 20 Torr and 1000 Torr.

At block 430 , method 400 includes 30 μm/hr, 40 μm/hr, 50 μm/hr, 55 μm/hr, 60 μm/hr, 70 μm/hr, 80 μm/hr, and 90-120 depositing at least one layer on the wafer at a deposition rate selected from the group consisting of μm/hr deposition rate, wherein the at least one layer comprises gallium, arsenic, nitrogen and indium, wherein the at least one layer comprises the at least one layer. The plurality of layers form a gallium arsenide cell.

In one aspect of method 400, the deposition temperature ranges from 680°C to 850°C for a 90-120 μm/hr deposition rate.

In another aspect of method 400, the nitrogen precursor gas comprises a compound selected from the group consisting of hydrazine, methylhydrazine, dimethylhydrazine, derivatives thereof, and combinations thereof.

In another aspect of method 400 , an n-type portion of a gallium arsenide cell is deposited over a sacrificial layer having a thickness between 1 nm and 20 nm, the sacrificial layer is disposed over the buffer layer and the buffer layer is disposed over the wafer. .

In another aspect of method 400 , the plurality of layers form an n-type gallium arsenide stack and a p-type gallium arsenide stack, wherein the n-type gallium arsenide stack comprises a first passivation layer having an emitter layer disposed on or over the first passivation layer, wherein the first passivation layer is disposed on or over the first contact layer, and the p-type gallium arsenide stack is disposed on or over the second passivation layer. It has two contact layers, a second passivation layer disposed on or over the absorber layer.

In another aspect of method 400, the deposition temperature may be between 400°C and 500°C.

In another aspect of method 400, the range of voltage force may be selected from the group consisting of 20 Torr to 760 Torr, 50 Torr to 450 Torr, and 100 Torr to 250 Torr.

5 shows an example of a method 500 for forming a cell, as implemented in some implementations herein.

At block 510 , method 500 includes heating a substrate comprising gallium and arsenic to a temperature between 550° C. and 900° C. in the process system.

At block 520 , the method 500 includes exposing the substrate to a deposition gas comprising a gallium arsenide precursor gas and arsine.

At block 530 , method 500 includes depositing an n-type contact layer comprising gallium and arsenic, wherein the n-type contact layer has a thickness of 100 nm or less.

At block 540 , the method 500 includes depositing an n-type passivation layer comprising gallium, aluminum and arsenic over the substrate, the n-type passivation layer having a thickness of 100 nm or less.

At block 550 , method 500 includes depositing an n-type absorber layer comprising gallium and arsenic over a substrate, wherein the n-type emitter layer has a thickness of 3000 nm or less.

At block 560 , the method 500 includes depositing a p-type passivation layer comprising gallium, aluminum and arsenic over the substrate, the p-type passivation layer having a thickness of 300 nm or less.

At block 570, the method 500 includes depositing a p-type contact layer comprising gallium and arsenic over the substrate, the p-type contact layer having a thickness of 100 nm or less, the n-type contact layer layer, n-type passivation layer, n-type absorber layer, p-type passivation layer, and p-type contact layer, respectively, 30 μm/hr, 40 μm/hr, 50 μm/hr, 55 μm/hr, Deposited at a deposition rate selected from the group consisting of 60 μm/hr, 70 μm/hr, 80 μm/hr, and 90-120 μm/hr deposition rates.

In another aspect of method 500 , the deposition temperature ranges from 680° C. to 850° C. for a deposition rate of 90-120 μm/hr.

In another aspect of method 500, the method comprises 30 μm/hr, 40 μm/hr, 50 μm/hr, 55 μm/hr, 60 μm/hr, 70 μm/hr, 80 μm/hr, and 90- and depositing on the substrate a sacrificial layer comprising aluminum and arsenic at a deposition rate selected from the group consisting of 120 μm/hr deposition rate, wherein the sacrificial layer has a thickness of 20 nm or less. The method comprises depositing an n-type contact layer over the sacrificial layer, depositing an n-type passivation layer over the n-type contact layer, depositing an n-type absorber layer over the n-type passivation layer; The method may further include depositing a p-type passivation layer over the p-type absorber layer, and depositing a p-type contact layer over the p-type passivation layer.

In another aspect of method 500, the method comprises at least a 30 μm/hr deposition rate, a 0 μm/hr deposition rate, a 50 μm/hr deposition rate, a 55 μm/hr deposition rate, and a 60 μm/hr deposition rate. depositing on the substrate a buffer layer comprising gallium and arsenic at a deposition rate selected from the group consisting of, wherein the buffer layer has a thickness of less than 300 nm. The method may further include depositing a sacrificial layer over the buffer layer.

In another aspect of method 500, the method comprises 30 μm/hr, 40 μm/hr, 50 μm/hr, 55 μm/hr, 60 μm/hr, 70 μm/hr, 80 μm/hr, and 90 μm/hr. and depositing on the substrate a sacrificial layer comprising aluminum and arsenic at a deposition rate selected from the group consisting of -120 μm/hr deposition rate, wherein the sacrificial layer has a thickness of 20 nm or less.

In another aspect of method 500, the method comprises 30 μm/hr, 40 μm/hr, 50 μm/hr, 55 μm/hr, 60 μm/hr, 70 μm/hr, 80 μm/hr, and 90 μm/hr. and depositing on the substrate a buffer layer comprising gallium and arsenic at a deposition rate selected from the group consisting of -120 μm/hr deposition rate, wherein the buffer layer has a thickness of less than 300 nm. The method may further comprise depositing a sacrificial layer over the buffer layer.

In another aspect of the method 500, exposing the substrate to the deposition gas further comprises exposing the substrate to a voltage force of 450 Torr or less or exposing the substrate to a voltage force of at least 780 Torr.

Although the above relates to the implementation of the present invention, within the basic scope, still further further implementations of the present invention may be devised, the scope of which is determined by the following claims.

Claims (30)

A method for forming a semiconductor material on a wafer, the method comprising:
heating the wafer to a deposition temperature of 550° C. to 900° C. in the process system;
exposing the wafer to a deposition gas comprising a gallium precursor gas and arsine at a voltage force of 20 Torr to 1000 Torr, and
Deposition selected from the group consisting of 30 μm/hr, 40 μm/hr, 50 μm/hr, 55 μm/hr, 60 μm/hr, 70 μm/hr, 80 μm/hr, and 90-120 μm/hr deposition rates. depositing one or more layers having gallium arsenide on the wafer at a rate
wherein the plurality of layers comprising the one or more layers form a gallium arsenide cell. The method of claim 1 , wherein for a deposition rate of 90-120 μm/hr, the deposition temperature ranges from 680°C to 850°C. The method of claim 1 , wherein the deposition gas further comprises an aluminum precursor gas and the gallium arsenide layer further comprises aluminum. 4. The method of claim 3, wherein the aluminum precursor gas comprises an alkyl aluminum compound. 5. The method of claim 4, wherein the alkyl aluminum compound is trimethylaluminum or triethylaluminum. The method of claim 1 , wherein the deposition gas further comprises a carrier gas comprising a mixture of hydrogen and argon. The semiconductor of claim 1 , wherein the n-type portion of the gallium arsenide cell is deposited over a sacrificial layer having a thickness of 1 nm to 20 nm, the sacrificial layer disposed over the buffer layer and the buffer layer disposed over the wafer. A method for forming a substance. According to claim 1,
the plurality of layers form an n-type gallium arsenide stack and a p-type gallium arsenide stack,
wherein the n-type gallium arsenide stack has an emitter layer disposed on or over a first passivation layer, wherein the first passivation layer is disposed on or over the first contact layer;
wherein the p-type gallium arsenide stack has a second contact layer disposed on or over a second passivation layer, wherein the second passivation layer is disposed on or over the absorber layer. Way. The method of claim 1 , wherein the deposition temperature ranges from 600°C to 800°C. According to claim 1, wherein the range of the voltage force is
20 Torr to 760 Torr,
50 Torr to 450 Torr, and
100 Torr to 250 Torr
A method for forming a semiconductor material selected from the group consisting of A method for forming a semiconductor material on a wafer, comprising:
heating the wafer to a deposition temperature of 550° C. to 900° C. in the process system;
exposing the wafer to a deposition gas comprising a gallium precursor gas, an aluminum precursor gas, and arsine at a voltage of 20 Torr to 1000 Torr, and
Deposition selected from the group consisting of 30 μm/hr, 40 μm/hr, 50 μm/hr, 55 μm/hr, 60 μm/hr, 70 μm/hr, 80 μm/hr, and 90-120 μm/hr deposition rates. depositing one or more layers on the wafer at a rate;
wherein the at least one layer comprises aluminum gallium arsenide and the plurality of layers comprising the at least one layer form a gallium arsenide cell. The method of claim 11 , wherein the deposition temperature ranges from 680° C. to 850° C. for a 90-120 μm/hr deposition rate. The semiconductor of claim 11 , wherein the n-type portion of the gallium arsenide cell is deposited over a sacrificial layer having a thickness of 1 nm to 20 nm, the sacrificial layer disposed over the buffer layer and the buffer layer disposed over the wafer. A method for forming a substance. 12. The method of claim 11,
the plurality of layers form an n-type gallium arsenide stack and a p-type gallium arsenide stack,
wherein the n-type gallium arsenide stack has an emitter layer disposed on or over a first passivation layer, the first passivation layer disposed on or over the first contact layer;
wherein the p-type gallium arsenide stack has a second contact layer disposed on or over a second passivation layer, wherein the second passivation layer is disposed on or over the absorber layer. Way. The method of claim 11 , wherein the deposition temperature ranges from 600°C to 800°C. 12. The method of claim 11, wherein the range of the voltage force is
20 Torr to 760 Torr,
50 Torr to 450 Torr, and
100 Torr to 250 Torr
A method for forming a semiconductor material selected from the group consisting of A method for forming a semiconductor material on a wafer, comprising:
heating the wafer to a deposition temperature of 550° C. to 900° C. in the process system;
exposing the wafer to a deposition gas comprising a gallium precursor gas, an indium precursor gas, a nitrogen precursor gas and arsine at a voltage of 20 Torr to 1000 Torr, and
Deposition selected from the group consisting of 30 μm/hr, 40 μm/hr, 50 μm/hr, 55 μm/hr, 60 μm/hr, 70 μm/hr, 80 μm/hr, and 90-120 μm/hr deposition rates. depositing one or more layers on the wafer at a rate;
wherein at least one layer comprises gallium, arsenic, nitrogen and indium, and wherein the plurality of layers comprising at least one layer form a gallium arsenide cell. The method of claim 17 , wherein the deposition temperature ranges from 680° C. to 850° C. for a deposition rate of 90-120 μm/hr. 18. The method of claim 17, wherein the nitrogen precursor gas comprises a compound selected from the group consisting of hydrazine, methylhydrazine, dimethylhydrazine, derivatives thereof, and combinations thereof. 18. The semiconductor of claim 17, wherein the n-type portion of the gallium arsenide cell is deposited over a sacrificial layer having a thickness of 1 nm to 20 nm, the sacrificial layer disposed over the buffer layer, the buffer layer disposed over the wafer. A method for forming a substance. 18. The method of claim 17,
the plurality of layers form an n-type gallium arsenide stack and a p-type gallium arsenide stack,
wherein the n-type gallium arsenide stack has an emitter layer disposed on or over a first passivation layer, the first passivation layer disposed on or over the first contact layer;
wherein the p-type gallium arsenide stack has a second contact layer disposed on or over a second passivation layer, wherein the second passivation layer is disposed on or over the absorber layer. Way. 18. The method of claim 17, wherein the deposition temperature is between 400°C and 500°C. 18. The method of claim 17, wherein the range of the voltage force is
20 Torr to 760 Torr,
50 Torr to 450 Torr, and
100 Torr to 250 Torr
A method for forming a semiconductor material selected from the group consisting of A method of forming a cell, comprising:
heating the substrate comprising gallium and arsenic to a temperature of 550° C. to 900° C. in the process system;
exposing the substrate to a deposition gas comprising a gallium precursor gas and arsine;
depositing an n-type contact layer comprising gallium and arsine over a substrate, wherein the n-type contact layer has a thickness of 100 nm or less;
depositing on the substrate an n-type passivation layer comprising gallium, aluminum, and arsenic, the n-type passivation layer having a thickness of 100 nm or less;
depositing an n-type absorber layer comprising gallium and arsenic over the substrate, the n-type emitter layer having a thickness of 3000 nm or less;
depositing over the substrate a p-type passivation layer comprising gallium, aluminum and arsenic, the p-type passivation layer having a thickness of 300 nm or less, and
depositing over a substrate a p-type contact layer comprising gallium and arsenic, the p-type contact layer having a thickness of 100 nm or less;
The n-type contact layer, the n-type passivation layer, the n-type absorber layer, the p-type passivation layer, and the p-type contact layer are 30 μm/hr, 40 μm/hr, 50 μm, respectively. A method of forming a cell, wherein the cell is deposited at a deposition rate selected from the group consisting of /hr, 55 μm/hr, 60 μm/hr, 70 μm/hr, 80 μm/hr, and 90-120 μm/hr deposition rate. The method of claim 24 , wherein the deposition temperature ranges from 680° C. to 850° C. for a deposition rate of 90-120 μm/hr. 25. The method of claim 24,
Deposition selected from the group consisting of 30 μm/hr, 40 μm/hr, 50 μm/hr, 55 μm/hr, 60 μm/hr, 70 μm/hr, 80 μm/hr, and 90-120 μm/hr deposition rates. depositing over the substrate a sacrificial layer comprising aluminum and arsenic at a rate, the sacrificial layer having a thickness of 20 nm or less;
depositing an n-type contact layer over the sacrificial layer;
depositing an n-type passivation layer over the n-type contact layer;
depositing an n-type absorber layer over the n-type passivation layer;
depositing a p-type passivation layer over the p-type absorber layer, and
and depositing a p-type contact layer over the p-type passivation layer. 27. The method of claim 26,
gallium and at a deposition rate selected from the group consisting of a 30 μm/hr deposition rate, a 40 μm/hr deposition rate, a 50 μm/hr deposition rate, a 55 μm/hr deposition rate, and a 60 μm/hr deposition rate or higher. depositing on the substrate a buffer layer comprising arsenic, the buffer layer having a thickness of less than 300 nm; and
depositing a sacrificial layer over the buffer layer;
Further comprising, a method of forming a cell. 25. The method of claim 24,
Deposition selected from the group consisting of 30 μm/hr, 40 μm/hr, 50 μm/hr, 55 μm/hr, 60 μm/hr, 70 μm/hr, 80 μm/hr, and 90-120 μm/hr deposition rates. and depositing over the substrate a sacrificial layer comprising aluminum and arsenic at a rate, the sacrificial layer having a thickness of 20 nm or less. 29. The method of claim 28,
Deposition selected from the group consisting of 30 μm/hr, 40 μm/hr, 50 μm/hr, 55 μm/hr, 60 μm/hr, 70 μm/hr, 80 μm/hr, and 90-120 μm/hr deposition rates. depositing on the substrate a buffer layer comprising gallium and arsenic at a rate, the buffer layer having a thickness of less than 300 nm; and
and depositing a sacrificial layer over the buffer layer. 25. The method of claim 24, wherein exposing the substrate to a deposition gas comprises:
exposing the substrate to a voltage force of 450 Torr or less, or
and exposing the substrate to a voltage force of at least 780 Torr.

Images