Process for forming electrically isolating high resistivity regions in GaAs

Claim 2

A process for forming electrical isolation barriers in gallium arsenide which comprises accelerating heavy ions with an atomic weight equal to or greater than the atomic weight of neon into selected regions of gallium arsenide and at accelerating voltages of approximately 20 KeV or less, while simultaneously heating said GaAs at elevated temperatures between about 200*C-500*C, said ions penetrating the surface of said GaAs to create arsenic vacancies therein, and thereafter diffusing deeper into the GaAs crystal under the influence of said elevated temperature to tie up extra electrons in said GaAs crystal and create arsenic vacancy complexes which raise the resistivity in said selected regions to the order of about 107 ohm centimeters or higher, whereby the resistivity of said isolation barriers formed will not be significantly lowered by annealing at temperatures below about 800*C, and the resistivity of said barriers will be sufficient to prevent any significant AC or DC coupling therethrough.

Claim 3

THE PROCESS DEFINED IN CLAIM 1 WHEREIN SAID HEAVY IONS ARE ARGON IONS.

Claim 4

The process defined in claim 1 wherein said heavy ions are selected from the group consisting of argon, neon, krypton and xenon ions.

Claim 5

A process for forming electrically isolated islands of single crystal gallium arsenide which includes: a. providing a substrate of suitable semiinsulating material, b. forming a single crystal layer of gallium arsenide on said substrate, and c. bombarding regions of said single crystal gallium arsenide layer with relatively heavy ions with an atomic weight equal to or greater than the atomic weight of neon and under the influence of an accelerating voltage of approximately 20 KeV or less, while simultaneously heating said GaAs at elevated temperatures between about 200*C - 500*C, said ions penetrating the surface of said GaAs to create arsenic vacancies therein, and thereafter diffusing deeper into the GaAs crystal under the influence of said elevated temperature to tie up extra electrons in said GaAs crystal and create arsenic vacancy complexes which raise the resistivity in said selected regions to the order of about 107 ohm centimeters, or higher, whereby said resistivity will not be substantially altered when subjected to annealing temperatures below about 800*C and said barriers will prevent any significant AC or DC coupling therethrough.

Claim 6

A process for forming electrically isolated islands of single crystal gallium arsenide which includes: a. providing a substrate of suitable semiinsulating material, b. forming a single crystal layer of gallium arsenide on said substrate, and c. bombarding regions of said single crystal gallium arsenide layer with relatively heavy ions with an atomic weight equal to or greater than the atomic weight of neon and under the influence of an accelerating voltage of approximately 20 KeV or less, while simultaneously heating said GaAs at elevated temperatures between about 200*C - 500*C, said ions penetrating the surface of said GaAs to create arsenic vacancies therein, and thereafter diffusing deeper into the GaAs crystal under the influence of said elevated temperature to tie up extra electrons in said GaAs crystal and create arsenic vacancy complexes which raise the resistivity in said selected regions to the order of about 107 ohm centimeters, or higher, whereby said resistivity will not be substantially altered when subjected to annealing temperatures below about 800*C and said barriers will prevent any significant AC or DC coupling therethrough.

Claim 7

The process defined in claim 4 wherein said heavy ions are argon ions.

Claim 8

The process defined in claim 4 wherein said heavy ions are selected from the group consisting of argon, neon, krypton and xenon ions.

Claim 9

The process defined in claim 4 which, prior to and during the ion bombardment of said epitaxial gallium arsenide layer, includes heating said substrate and epitaxial layer to approximately 400*C to thereby enhance the creation of vacancy complexes in said epitaxial layer and thereby raise the resistivity thereof.

Claim 10

The process defined in claim 7 wherein said heavy ions are selected from the group consisting of argon, neon, krypton and xenon ions.

Claim 11

The process defined in claim 4 which, prior to the ion bombardment of said epitaxial gallium arsenide layer, includes: a. forming a plurality of spaced metal electrodes on said epitaxial layer for making ohmic contact to devices thereunder; and b. using said electrodes as a mask against ion implantation to thereby provide the selective bombardment of said epitaxial layer and the electrical isolation of said devices.

Claim 12

The process defined in claim 4 which, prior to the ion bombardment of said epitaxial gallium arsenide layer, includes forming a plurality of spaced Schottky barrier electrodes on the surface of said epitaxial layer to thereby form a plurality of Schottky barrier diodes in said epitaxial layer, whereby said electrodes Serve as a mask against ion implantation into said epitaxial layer, leaving a plurality of electrically isolated Schottky barrier diodes therein exhibiting high reverse breakdown voltages.

Claim 13

The process defined in claim 10 wherein said inert ions are argon ions.

Claim 14

The process defined in claim 10 wherein said heavy ions are selected from the group consisting of argon, neon, krypton and xenon ions.

Claim 15

The process defined in claim 12 which, prior to and during the ion bombardment of said epitaxial gallium arsenide layer, includes heating said substrate and epitaxial layer to approximately 400*C to thereby enhance the creation of vacancy complexes in said epitaxial layer and thereby raise the resistivity thereof.