Recent advances in InAs avalanche photodiodes

InAs possesses nearly ideal material properties for the fabrication of near- and mid-infrared avalanche photodiodes (APDs). Because electron impact ionization in InAs is greatly favored over hole impact ionization, InAs multiplication regions exhibit several appealing characteristics, including extremely low excess noise factors and bandwidth independent of gain. These properties make InAs APDs attractive for a number of near- and mid-infrared sensing applications including remote gas sensing, light detection and ranging (LIDAR), and both active and passive imaging. Compared to HgCdTe, the dominant mid-infrared APD technology, InAs possesses several distinct advantages including comparatively simple growth, inherent compositional uniformity, and the availability of relatively low-cost, lattice-matched, substrates with low defect densities. These advantages are particularly compelling for the fabrication of large-area focal plane arrays (FPA), where high pixel yield is essential.