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US 4,106,959 AGranted
Producing high efficiency gallium arsenide IMPATT diodes utilizing a gas injection system
AssigneeBell Telephone Laboratories, Incorporated
InventorsJames Vincent DiLorenzo, William Charles Niehaus, Lawrence John Varnerin, Jr.
Life of this patent
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Abstract
The operating frequency of an IMPATT diode depends on the width of the depletion region formed during operation. The frequency of high efficiency GaAs IMPATT diodes comprising a non-uniformly doped depletion region contacted by a rectifying barrier can be more precisely fixed by forming a "clump" of charge at exactly the depth below the surface contacted by the rectifying barrier corresponding to the desired depletion region.
Claims6
A process for making a gallium arsenide diode comprising:
- a. epitaxially depositing at least one layer of gallium arsenide on the surface of a gallium arsenide substrate from materials including a source of gallium, a source of arsenic, and a conductivity-type determining impurity;
- b. varying the amount of conductivity-type determining impurity during the epitaxial deposition in the following sequence:
- (1) raising the amount of impurity, (2) lowering the amount of impurity, and (3) raising the amount of impurity this sequence being timed such that a relatively thin region of the layer, ranging in thickness from 100 Angstroms to 0.5 .mu.m, is deposited while the impurity level is raised, so as to form a layer having a first relatively thin region formed during step 1 and a second relatively thin region formed during step 3 both of which regions having an impurity concentration that is relatively high with respect to the bulk of the layer,
- c. forming an electrical contact to the gallium arsenide substrate;
- and
- d. forming a rectifying barrier contact on the deposited gallium arsenide layer.
3 more elements
Dependencies are inferred from the claim text.