Rca Inc.

At&t Bell Laboratories

American Telephone & Telegraph Co., At&t Bell Laboratories

John R Zuber

Stephen R Forrest

George J Zydzik

Shobha Singh

Irfan Camlibel

Legrand G Van Uitert

Mahmoud A Hamamsy

Mahmoud A ElHamamsy

Herbert Foxman

An InGaAs photodiode is described in which a double layer of silicon nitride on the front surface serves several functions; both layers passivate the surface; an opening in the lower layer provides a diffusion mask for forming the p-n junction; and a narrower opening in the upper silicon nitride layer provides a deposition mask for forming a restricted area contact. In order to reduce strain near the junction, and hence reduce leakage currents and enhance reliability, the contact geometry has a narrow pedestal portion which contacts the surface in a zone remote from the junction edges and has a wider cap portion which is formed on the pedestal portion to seal the surface from the introduction of contaminants. The photodiode may be back-illuminated or front-illuminated.

Restricted contact planar photodiode

A back-illuminated InGaAs photodiode is described in which a double layer of silicon nitride on the front surface serves several functions; both layers passivate the surface; an opening in the lower layer provides a diffusion mask for forming the p-n junction; and a narrower opening in the upper silicon nitride layer provides a deposition mask for forming a restricted area contact. In order to reduce strain near the junction, and hence reduce leakage currents and enhance reliability, the contact geometry has a narrow pedestal portion which contacts the surface in a zone remote from the junction edges and has a wider cap portion which is formed on the pedestal portion to seal the surface from the introduction of contaminants.

Restricted contact, planar photodiode

A process is described for fabricating various optical devices including photodiodes in which a protective dielectric layer is put down on the surface of the device prior to heating to temperatures over about 250-300 degrees C. Such devices have excellent performance characteristics including low dark current and low noise figures.

Preparation of photodiodes

A solution of tetramethylammonium hydroxide and a surfactant in a lower alcohol solubilizes photoresist films without attacking materials found in integrated circuit devices so that a subsequent 1,1,1-trichloroethane rinse completely removes the photoresist.

Method of stripping photoresist

Mixtures of 1-propanol, water and certain perfluoro compounds form excellent drying agents for silicon based devices. The mixtures have good wetting properties and form azeotropic mixtures in the vapor phase.

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Piscataway, NJ, United States of America

John R Zuber