Reduction of surface recombination current in GaAs devices
AssigneeBell Telephone Laboratories, Incorporated
InventorsHorace C. Casey, Jr., Alfred Y. Cho, Philip W. Foy
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Abstract
Surface recombination current in GaAs devices is reduced by means of a semi-insulating, oxygen, iron or chromium doped monocrystalline layer of AlGaAs grown by MBE. The AlGaAs layer is grown on a GaAs body and is then masked. Diffusion of suitable impurities through a window in the mask converts the exposed portions of the AlGaAs layer to low resistivity and modifies the conductivity of the underlying zone of the GaAs body. The peripheral portions of the AlGaAs layer, however, remain semi-insulating and are effective to reduce the surface recombination velocity - diffusion length product by more than an order of magnitude.
Claims8
A GaAs device with reduced surface recombination current comprising
- a monocrystalline GaAs body (10) having a localized zone (26) of conductivity different from adjacent portions of said body,
- a monocrystalline layer (16) of oxygen-doped AlGaAs on a major surface of said body, said AlGaAs layer having a low resistivity central portion (16.2) in substantial registration with said zone and a semi-insulating peripheral portion (16.1) surrounding said central portion,
- a dielectric passivation layer (18) covering said peripheral portion of said AlGaAs layer,
- a first electrical contact (20) to said central portion of said AlGaAs layer, and
- a second electrical contact (24) to said body.
Dependencies are inferred from the claim text.