US4190470A — Production of epitaxial layers by vapor depositio…

Claim 1

Independent Claim 199 words

A method of producing an epitaxial layer of a compound comprising a first material selected from the group consisting of boron, aluminum, gallium, indium and mixtures thereof and a second material selected from the group consisting of phosphorus, arsenic, antimony and mixtures thereof, said method comprising, passing a carrier gas flow through a liquid halide of said second material to obtain a first vapor containing a halogen, carrier gas and second material as a raw reactor input vapor, while monitoring said carrier gas flow and adjusting it to obtain a predetermined mass of halogen and second material in said raw vapor, and forming a final reactor input vapor while maintaining a constant flow rate of said final vapor at a constant concentration of second material by monitoring the total volume of carrier gas in said raw vapor as added per unit of time and adjusting said raw vapor by adding a volume of additional carrier gas to form said final vapor, passing said final vapor to a source of said first material in a reactor where a reaction takes place, passing the products of said reaction to a seed crystal and depositing said epitaxial layer on said seed crystal.

Claim 2

Independent Claim 199 words

A method of producing an epitaxial layer of a compound comprising a first material selected from the group consisting of boron, aluminum, gallium, indium and mixtures thereof and a second material selected from the group consisting of phosphorus, arsenic, antimony and mixtures thereof, said method comprising, passing a carrier gas flow through a liquid halide of said second material to obtain a first vapor containing a halogen, carrier gas and second material as a raw reactor input vapor, while monitoring said carrier gas flow and adjusting it to obtain a predetermined mass of halogen and second material in said raw vapor, and forming a final reactor input vapor while maintaining a constant flow rate of said final vapor at a constant concentration of second material by monitoring the total volume of carrier gas in said raw vapor as added per unit of time and adjusting said raw vapor by adding a volume of additional carrier gas to form said final vapor, passing said final vapor to a source of said first material in a reactor where a reaction takes place, passing the products of said reaction to a seed crystal and depositing said epitaxial layer on said seed crystal.

Claim 3

Dependent Claim 73 words

A method in accordance with claim 1 wherein said carrier gas flow is passed through a vaporizer controller and then bubbled through said liquid halide with the resultant vapor monitored to determine mass of the halide picked up in the flow and said carrier gas flow passing to said bubbler is controlled to keep said last-mentioned mass constant while varying flow of raw vapor and concentration of halide in the resultant raw vapor.

Claim 4

Dependent Claim 37 words

A method in accordance with the method of claim 2 wherein the total flow per unit time of carrier gas to said bubbler and carrier gas added to said raw vapor is equal to a predetermined constant.

Claim 5

Dependent Claim 36 words

A method in accordance with the method of claim 3 wherein said carrier gas flow added to said raw vapor is passed through a mass flow controller operatively responsive to carrier gas flow to said bubbler.

Claim 6

Dependent Claim 13 words

A method in accordance with claim 1 wherein said compound is gallium arsenide.

Claim 7

Dependent Claim 13 words

A method in accordance with claim 2 wherein said compound is gallium arsenide.

Claim 8

Dependent Claim 13 words

A method in accordance with claim 3 wherein said compound is gallium arsenide.

Claim 9

Dependent Claim 13 words

A method in accordance with claim 4 wherein said compound is gallium arsenide.

Claim 10

Dependent Claim 13 words

A method in accordance with claim 1 wherein said carrier gas is hydrogen.

Claim 11

Dependent Claim 13 words

A method in accordance with claim 2 wherein said carrier gas is hydrogen.

Claim 12

Dependent Claim 13 words

A method in accordance with claim 3 wherein said carrier gas is hydrogen.

Claim 13

Dependent Claim 13 words

A method in accordance with claim 5 wherein said carrier gas is hydrogen.

Claim 14

Dependent Claim 13 words

A method in accordance with claim 1 wherein said compound is indium phosphide.

Claim 15

Dependent Claim 14 words

A method in accordance with claim 5 wherein said liquid halide is arsenic trichloride.

Claim 16

Dependent Claim 95 words

In method of forming an epitaxial layer of a compound selected from the group consisting essentially of gallium aluminum arsenide, gallium arsenide and indium phosphide by a transport reaction wherein a carrier gas is passed through a liquid halide to form a raw reactor input vapor flow which is passed to a reactor input, the improvement comprising, monitoring the concentration and flow rate of the raw reactor input vapor and adjusting to a predetermined flow rate and concentration by adjustment of an amount of additional carrier gas flow added to said raw reactor input vapor.

Claim 17

Dependent Claim 95 words

In method of forming an epitaxial layer of a compound selected from the group consisting essentially of gallium aluminum arsenide, gallium arsenide and indium phosphide by a transport reaction wherein a carrier gas is passed through a liquid halide to form a raw reactor input vapor flow which is passed to a reactor input, the improvement comprising, monitoring the concentration and flow rate of the raw reactor input vapor and adjusting to a predetermined flow rate and concentration by adjustment of an amount of additional carrier gas flow added to said raw reactor input vapor.

Claim 18

Dependent Claim 49 words

The improvement of claim 15 wherein said compound is gallium arsenide, and said monitoring is carried out by constantly measuring carrier gas flow to said liquid halide and adjusting the amount of additional carrier gas flow to have a predetermined constant value of carrier gas flow to said reactor.

Claim 19

Independent Claim 152 words

A method of maintaining a constant flow rate in a reactor for producing an epitaxial layer of a compound comprising a first material selected from the group consisting of boron, aluminum, gallium, indium and mixtures thereof and a second material selected from the group consisting of phosphorus, arsenic, antimony and mixtures thereof, wherein a flow of reactor input vapor carrying said second material and a halogen is passed to a reactor at a first reaction zone having a source of said first material and the resultant vapor then passed to a second zone carrying a seed crystal where said epitaxial layer of said compound is formed, said method comprising, introducing a supplementary constant volume vapor flow at a predetermined concentration in said reactor of a third material selected from the group consisting essentially of a diluent gas, dopant and mixtures thereof, and changing said predetermined concentration while maintaining said constant volume flow.

Claim 20

Independent Claim 152 words

A method of maintaining a constant flow rate in a reactor for producing an epitaxial layer of a compound comprising a first material selected from the group consisting of boron, aluminum, gallium, indium and mixtures thereof and a second material selected from the group consisting of phosphorus, arsenic, antimony and mixtures thereof, wherein a flow of reactor input vapor carrying said second material and a halogen is passed to a reactor at a first reaction zone having a source of said first material and the resultant vapor then passed to a second zone carrying a seed crystal where said epitaxial layer of said compound is formed, said method comprising, introducing a supplementary constant volume vapor flow at a predetermined concentration in said reactor of a third material selected from the group consisting essentially of a diluent gas, dopant and mixtures thereof, and changing said predetermined concentration while maintaining said constant volume flow.

Claim 21

Dependent Claim 69 words

A method in accordance with claim 17 and further comprising said third material comprising a diluent gas and dopant mixture, and being formed by mixing to obtain a first concentration of dopant in diluent gas, and adding additional diluent gas in an amount sufficient to maintain said predetermined concentration of dopant, and subsequently changing said last-mentioned concentration to obtain a variation in dopant concentration at a second predetermined concentration.

Claim 22

Independent Claim 134 words

A method of providing a constant flow rate in a reactor for producing an epitaxial layer of a compound comprising a first material selected from the group consisting of boron, aluminum, gallium, indium and mixtures thereof and a second material selected from the group consisting of phosphorus, arsenic, antimony and mixtures thereof, wherein a flow of reactor input vapor carrying said second material and a halogen is passed to a reactor at a first reaction zone having a source of said first material and the resultant vapor then passed to a second zone carrying a seed crystal where said epitaxial layer of said compound is formed, said method comprising, monitoring dopant gas flow rate to said reactor and adding supplementary diluent gas thereto to maintain said dopant gas flow at a predetermined constant value.

Claim 23

Independent Claim 134 words

A method of providing a constant flow rate in a reactor for producing an epitaxial layer of a compound comprising a first material selected from the group consisting of boron, aluminum, gallium, indium and mixtures thereof and a second material selected from the group consisting of phosphorus, arsenic, antimony and mixtures thereof, wherein a flow of reactor input vapor carrying said second material and a halogen is passed to a reactor at a first reaction zone having a source of said first material and the resultant vapor then passed to a second zone carrying a seed crystal where said epitaxial layer of said compound is formed, said method comprising, monitoring dopant gas flow rate to said reactor and adding supplementary diluent gas thereto to maintain said dopant gas flow at a predetermined constant value.

Claim 24

Dependent Claim 67 words

A method in accordance with the method of claim 19 and further comprising diluting said dopant gas flow to a first value by means of a plural array of mass flow controllers capable of electrical actuation to a variety of predetermined flow conditions and further diluting said dopant gas flow by addition of a minor amount of supplementary diluent gas added to maintain a constant flow rate.

Claim 25

Dependent Claim 29 words

A method in accordance with the method of claim 1 and further comprising adding a constant volume flow of diluent gas to said reactor along with said final vapor.

Claim 26

Dependent Claim 19 words

A method in accordance with the method of claim 21 and further comprising said diluent gas carrying a dopant.

Claim 27

Dependent Claim 33 words

A method in accordance with the method of claim 22 and further comprising varying the concentration of dopant in said diluent gas while maintaining a constant gas flow rate thereof to said reactor.

Claim 28

Dependent Claim 49 words

A method in accordance with the method of claim 23 wherein said last-mentioned constant flow rate is obtained by electrically monitoring flow of a dopant diluent gas mixture through an electrically actuated mass flow controller and electrically actuating a second mass flow controller to provide a predetermined flow rate.

Claim 29

Dependent Claim 13 words

A method in accordance with claim 24 wherein said compound is gallium arsenide.

Claim 30

Dependent Claim 13 words

A method in accordance with claim 19 wherein said compound is gallium arsenide.

Claim 31

Dependent Claim 13 words

A method in accordance with claim 18 wherein said compound is gallium arsenide.

Claim 32

Dependent Claim 162 words

In a method of producing an epitaxial layer of a compound comprising a first material selected from the group consisting of boron, aluminum, gallium, indium and mixtures thereof and a second material selected from the group consisting of phosphorus, arsenic, antimony and mixtures thereof, the steps comprising passing a carrier gas flow through a liquid halide of said second material to obtain a first vapor containing a halogen, carrier gas and second material as a raw reactor input vapor, while monitoring said carrier gas flow and adjusting it to obtain a predetermined mass of halogen and second material in said raw vapor, and forming a final reactor input vapor while maintaining a constant flow rate of said final vapor at a constant concentration of second material by monitoring the total volume of carrier gas in said raw vapor as added per unit of time and adjusting said raw vapor by adding a volume of additional carrier gas to form said final vapor.

Claim 33

Dependent Claim 162 words

In a method of producing an epitaxial layer of a compound comprising a first material selected from the group consisting of boron, aluminum, gallium, indium and mixtures thereof and a second material selected from the group consisting of phosphorus, arsenic, antimony and mixtures thereof, the steps comprising passing a carrier gas flow through a liquid halide of said second material to obtain a first vapor containing a halogen, carrier gas and second material as a raw reactor input vapor, while monitoring said carrier gas flow and adjusting it to obtain a predetermined mass of halogen and second material in said raw vapor, and forming a final reactor input vapor while maintaining a constant flow rate of said final vapor at a constant concentration of second material by monitoring the total volume of carrier gas in said raw vapor as added per unit of time and adjusting said raw vapor by adding a volume of additional carrier gas to form said final vapor.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1983-02-25	1983-08-27	1984-02-26	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1987-02-25	1987-08-27	1988-02-26	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1991-02-25	1991-08-27	1992-02-26	$7700.00	Window Closed / Lapsed

Production of epitaxial layers by vapor deposition utilizing dynamically adjusted flow rates and gas phase concentrations

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