Monolithic InGaAs JFET active-pixel tunable image sensor (MAPTIS)

Abstract

A new monolithic InGaAs active pixel multispectral image sensor is described. This infrared sensor will utilize high quality InGaAs grown by molecular beam epitaxy on InP substrate for the fabrication of a high speed junction field effect transistor array. In_1-xGa_xAs is a III-V alloy whose cutoff wavelength can be tuned from 0.8 micrometer (GaAs) to 3.5 micrometer (InAs). Due to the spectral windows of 3 - 5 micrometer and 8 - 12 micrometer in atmosphere, this material has not received much attention to date for infrared focal plane arrays even though the responsivities for the 0.8 - 1.0 micrometer, and 2.0 - 2.5 micrometer windows for the water and carbon dioxide molecules in air are excellent. Steady advancements of InGaAs material growth and devices have been made, primarily driven by the optoelectronics industry and the high speed electronics community. Most of this knowledge exists in the public domain and is readily accessible. Detectors at 1.7 micrometer cutoff can be ideally implemented as lattice matched In_0.53Ga_0.47As/InP PIN devices. PIN detectors require high material quality to reduce dark current and decrease bit errors. Additionally, the high intrinsic mobility of In_0.53Ga_0.47As enables very high speed transistors for monolithic microwave integrated circuit applications. The new active pixel sensor technology, a likely successor to charge coupled device, has been successfully developed for low noise, high signal transfer efficiency imaging circuits in silicon at JPL. The silicon active pixel sensor technology is being adapted to InGaAs/InP in this exploratory development effort. In this paper, a preliminary result of the monolithic multispectral (visible/near infrared/short-wavelength infrared) active pixel imaging sensor is discussed for application in transportable shipboard surveillance, night vision and emission spectroscopy.