Back-illuminated heterojunction photodiode

US6483130B1 · kind B1 · utility

Assignee

• HONEYWELL INTERNATIONAL INC. · US

Inventors

• Wei Yang · Minnetonka, US
• Thomas E. Nohava · Apple Valley, US
• Scott A. McPherson · Eagan, US
• Robert C. Torreano · Coon Rapids, US
• Subash Krishnankutty · North Haven, US
• Holly A. Marsh · St. Louis Park, US

Key dates

• Filing date: Mar 24, 1999
• Grant date: Nov 19, 2002
• Expiry date: Mar 24, 2019

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02E10/544

Abstract

A p-i-n photodiode having a high responsivity and quantum efficiency due to an AlGaN heterojunction where photons are absorbed within the p-n junction thereby eliminating carrier losses due to surface recombination and diffusion processes. Ultraviolet light comes through a transparent substrate, such as sapphire, a transparent AlN buffer and an n-doped AlGaN layer, and to an undoped AlGaN layer where the light is absorbed. The undoped layer is sandwiched between the n-doped AlGaN layer and a p-doped AlGaN layer. Metal contacts are formed on the doped layers to obtain the current caused by the absorbed light in the undoped layer. The mole fractions of the Al and Ga in the undoped and doped layers may be adjusted to obtain a desired wavelength bandpass of light to be detected.