Method of high growth rate deposition for group III/V materials
Embodiments of the invention generally relate processes for epitaxial growing Group III/V materials at high growth rates, such as about 30 μm/hr or greater, for example, about 40 μm/hr, about 50 μm/hr, about 55 μm/hr, about 60 μm/hr, or greater. The deposited Group III/V materials or films may be utilized in solar, semiconductor, or other electronic device applications. In some embodiments, the Group III/V materials may be formed or grown on a sacrificial layer disposed on or over the support substrate during a vapor deposition process. Subsequently, the Group III/V materials may be removed from the support substrate during an epitaxial lift off (ELO) process. The Group III/V materials are thin films of epitaxially grown layers which contain gallium arsenide, gallium aluminum arsenide, gallium indium arsenide, gallium indium arsenide nitride, gallium aluminum indium phosphide, phosphides thereof, nitrides thereof, derivatives thereof, alloys thereof, or combinations thereof.
1. A method for forming a gallium arsenide material on a wafer, comprising:
heating a wafer to a deposition temperature of greater than 650 C and less than 750 C within a processing system;
exposing the wafer to a deposition gas comprising a gallium precursor gas and arsine at a total pressure of greater than 50 Torr and less than 450 Torr; and
depositing one or more gallium arsenide layers on the wafer 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, wherein multiple gallium arsenide layers, including the one or more gallium arsenide layers, form a gallium arsenide cell, wherein a n-type portion of the gallium arsenide cell is deposited over a sacrificial layer having a thickness between 1 and 20 nm, which is disposed over a buffer layer, which is disposed over the wafer, wherein the gallium arsenide cell comprises a n-type gallium arsenide stack and a p-type gallium arsenide stack, wherein said n-type gallium arsenide stack comprises an emitter layer disposed on or over a first passivation layer disposed on or over a first contact layer and said p-type gallium arsenide stack comprises a second contact layer disposed on or over a second passivation layer, disposed on or over an absorber layer, and wherein said emitter layer and said absorber layer contain gallium arsenide and are formed using a first mixture of 10 cc of arsine in 2,000 cc of hydrogen gas and 200 cc of a second mixture of 10% trimethylgallium in hydrogen gas.
2. The method of claim 1 , wherein the deposition gas further comprises an aluminum precursor gas and the gallium arsenide layer further comprises aluminum.
3. The method of claim 2 , wherein the aluminum precursor gas comprises an alkyl aluminum compound.
4. The method of claim 3 , wherein the alkyl aluminum compound is trimethylaluminum or triethylaluminum.
5. The method of claim 1 , wherein the deposition gas further comprises a carrier gas comprising a mixture of hydrogen and argon.
6. A method for forming a gallium arsenide material on a wafer, comprising:
heating a wafer to a deposition temperature of greater than 650 C and less than 750 C within a processing system;
exposing the wafer to a deposition gas comprising a gallium precursor gas, an aluminum precursor gas, and arsine at a total pressure of greater than 50 Torr and less than 450 Torr; and
depositing one or more gallium arsenide layers on the wafer 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, wherein the one or more gallium arsenide layers comprise aluminum gallium arsenide, wherein multiple gallium arsenide layers, including the one or more gallium arsenide layers, form a gallium arsenide cell, wherein a n-type portion of the gallium arsenide cell is deposited over a sacrificial layer having a thickness between 1 and 20 nm, which is disposed over a buffer layer, which is disposed over the wafer, wherein the gallium arsenide cell comprises a n-type gallium arsenide stack and a p-type gallium arsenide stack, wherein said n-type gallium arsenide stack comprises an emitter layer disposed on or over a first passivation layer disposed on or over a first contact layer and said p-type gallium arsenide stack comprises a second contact layer disposed on or over a second passivation layer, disposed on or over an absorber layer, and wherein said emitter layer and said absorber layer contain gallium arsenide, and said first and second passivation layers are formed using a first mixture of 10 cc of arsine in 2,000 cc of hydrogen gas, 200 cc of a second mixture of 10% trimethylgallium in hydrogen gas and 200 cc of a third mixture of 1% trimethylaluminum in hydrogen gas.
7. A method for forming a Group III/V material on a wafer, comprising:
heating a wafer to a deposition temperature of greater than 400 C and less than 500 C within a processing 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 total pressure of greater than 50 Torr and less than 450 Torr; and
depositing one or more Group III/y layers on the wafer 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, wherein the one or more Group III/V layers comprise gallium, arsenic, nitrogen and indium, wherein multiple Group III/V layers, including the one or more Group layers, form a gallium arsenide cell, wherein a n-type portion of the gallium arsenide cell is deposited over a sacrificial layer having a thickness between 1 and 20 nm, which is disposed over a buffer layer, which is disposed over the wafer, wherein the gallium arsenide cell comprises a n-type gallium arsenide stack and a p-type gallium arsenide stack, wherein said n-type gallium arsenide stack comprises an emitter layer disposed on or over a first passivation layer disposed on or over a first contact layer and said p-type gallium arsenide stack comprises a second contact layer disposed on or over a second passivation layer, disposed on or over an absorber layer, and wherein said emitter layer and said absorber layer contain gallium arsenide are formed using a first mixture of 10 cc of arsine in 2,000 cc of hydrogen gas, 200 cc of a second mixture of 10% trimethylgallium in hydrogen gas and 200 cc of a third mixture of 1% trimethylindium in hydrogen gas.
8. The method of claim 7 , wherein the nitrogen precursor gas comprises a compound selected from the group consisting of hydrazine, methylhydrazine, dimethylhydrazine, derivatives thereof, and combinations thereof.
9. A method of forming a gallium arsenide cell, comprising:
heating a substrate comprising gallium and arsine to a temperature of greater than 550 C within a processing 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 the substrate at deposition rate selected from the group consisting of a 30 μm/hr deposition rate, a 40 μ/hr deposition rate, a 50 μm/hr deposition rate, a 55 μm/hr deposition rate, and a 60 μm/hr deposition rate, the n-type contact layer having a thickness of 100 nm or less;
depositing an n-type passivation layer comprising gallium and arsine over the substrate 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, the n-type passivation layer having a thickness of 100 nm or less;
depositing an n-type emitter layer comprising gallium and arsine over the substrate using a first mixture of 10 cc of arsine in 2,000 cc of hydrogen gas, 200 cc of a second mixture of 10% trimethylgallium in hydrogen gas, 200 cc of a third mixture of 1% trimethylindium in hydrogen gas, and a fourth mixture of 10 cc of phosphine in 2,000 cc of hydrogen gas at a deposition rate of 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, the n-type emitter layer having a thickness of 1,200 nm or less;
depositing a p-type absorber layer comprising gallium and arsine over the substrate using the first mixture of 10 cc of arsine in 2,000 cc of hydrogen gas, 200 cc of the second mixture of 10% trimethylgallium in hydrogen gas, 200 cc of the third mixture of 1% trimethylindium in hydrogen gas, and the fourth mixture of 10 cc of phosphine in 2,000 cc of hydrogen gas 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, the p-type absorber layer having a thickness of 3,000 nm or less;
depositing a p-type passivation layer comprising gallium and arsine over the substrate 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, the p-type passivation layer having a thickness of 300 nm or less; and
depositing a p-type contact layer comprising gallium and arsine over the substrate 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, the p-type contact layer having a thickness of 100 nm or less.
10. The method of claim 9 , further comprising:
depositing a sacrificial layer comprising aluminum and arsine over the substrate 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, the sacrificial layer having a thickness of 20 nm or less;
depositing the n-type contact layer on the sacrificial layer;
depositing the n-type passivation layer on the n-type contact layer;
depositing the n-type emitter layer on the n-type passivation layer;
depositing the p-type absorber layer on the n-type emitter layer;
depositing the p-type passivation layer on the p-type absorber layer; and
depositing the p-type contact layer on the p-type passivation layer.
11. The method of claim 10 , further comprising:
depositing a buffer layer comprising gallium and arsine on the substrate 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, the buffer layer having a thickness of less than 300 nm; and
depositing the sacrificial layer on the buffer layer.
12. The method of claim 9 , further comprising:
depositing a sacrificial layer comprising aluminum and arsine over the substrate 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, the sacrificial layer having a thickness of 20 nm or less;
depositing the p-type contact layer on the sacrificial layer;
depositing the p-type passivation layer on the p-type contact layer;
depositing the p-type absorber layer on the p-type passivation layer;
depositing the n-type emitter layer on the p-type absorber layer;
depositing the n-type passivation layer on the n-type emitter layer; and
depositing the n-type contact layer on the n-type passivation layer.
13. The method of claim 12 , further comprising:
depositing a buffer layer comprising gallium and arsine on the substrate 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, the buffer layer having a thickness of less than 300 nm; and
depositing the sacrificial layer on the buffer layer.
14. The method of claim 9 , wherein exposing the substrate to a deposition gas further comprises exposing the substrate to a total pressure of 450 Torr or less.
15. The method of claim 9 , wherein exposing the substrate to a deposition gas further comprises exposing the substrate to a total pressure of at least 780 Torr.