CMOS‐Compatible Short‐Wave Infrared Linear Arrays of Ge‐on‐Si Avalanche Photodiodes

Germanium‐containing short‐wave infrared (SWIR) avalanche photodiode (APD) arrays on silicon platforms have the potential for monolithic integration into complementary metal‐oxide‐semiconductor (CMOS) integrated circuits, making them mass‐manufacturable, high‐performance, arrayed optical detectors operating at wavelengths beyond the silicon cut‐off wavelength. Here, the first high‐performance, surface‐illuminated, 10‐pixel linear array of pseudoplanar geometry germanium‐on‐silicon (Ge‐on‐Si) APDs operating at 1550 nm wavelength and at temperatures up to 378 K are demonstrated. At room temperature, the dark current, avalanche gain, responsivity, and avalanche breakdown of the devices show good uniformity. Array A exhibits a mean dark current density of 198 ± 62 mA cm⁻² at 90% of the breakdown voltage. The excess noise factor is less than half that of InP‐based SWIR APD arrays, which allows Ge‐on‐Si devices to operate at a higher avalanche gain. A responsivity of 8.2 A W⁻¹ at a gain of 20 and excess noise of 3.3 is achieved when illuminated with 1550 nm wavelength light. The detector array also demonstrates stable performance at 378 K with a maximum avalanche gain of 24. This device architecture will be applicable for the design of large‐scale APD arrays on Si platforms for SWIR detection which can be used in imaging, sensing, and optical communication applications.