Mid-wavelength infrared avalanche photodetector with AlAsSb/GaSb superlattice

Jiakai Li,Arash Dehzangi,Gail Brown,Manijeh Razeghi

doi:10.1038/s41598-021-86566-8

Abstract

In this work, a mid-wavelength infrared separate absorption and multiplication avalanche photodiode (SAM-APD) with 100% cut-off wavelength of ~ 5.0 µm at 200 K grown by molecular beam epitaxy was demonstrated. The InAsSb-based SAM-APD device was designed to have electron dominated avalanche mechanism via the band structure engineered multi-quantum well structure based on AlAsSb/GaSb H-structure superlattice and InAsSb material in the multiplication region. The device exhibits a maximum multiplication gain of 29 at 200 K under -14.7 bias voltage. The maximum multiplication gain value for the MWIR SAM-APD increases from 29 at 200 K to 121 at 150 K. The electron and hole impact ionization coefficients were derived and the large difference between their value was observed. The carrier ionization ratio for the MWIR SAM-APD device was calculated to be ~ 0.097 at 200 K.

Highlights

In this work, a mid-wavelength infrared separate absorption and multiplication avalanche photodiode (SAM-avalanche photodiodes (APDs)) with 100% cut-off wavelength of ~ 5.0 μm at 200 K grown by molecular beam epitaxy was demonstrated
Due to the great band structure engineering flexibility, an antimonide-based SLS can be used as the barrier layer for a multi-quantum well (MQW) heterostructure when combined with an InAsSb well
The separate absorption layer used in the separate absorption and multiplication avalanche photodiode (SAM-APD) is an InAsSb alloy chosen to cover the mid-infrared range at an operating temperature of 150 K

Summary

Methods

The wafer was fabricated into the two-contact mesa-isolated devices with the sizes varying from 40 × 40 μm[2] to 300 × 300 μm[2] using our standard single element photodiode fabrication steps. The photolithography was first used to create the pattern of mesa shapes and sizes on the photoresist above the sample. The combination of inductively coupled plasma-reactive ion etching (ICP-RIE) and wet etching was used to transfer the pattern of the photomask onto the sample to define the shape of the mesa. The window to the metal contacts was opened by performing another photolithography and removing the S iO2 by reactive ion etching. The relative spectral response of the InAsSb-based MWIR SAM-APD was measured at both 150 K and 200 K under front-side illumination using a Bruker IFS 66v/S Fourier transform infrared spectrometer (FTIR). A 633 nm He–Ne laser with an incident power of 5.0 mW was used to measure the photocurrent and the gain of the APDs at temperature range from 150 to 250 K

Author contributions

Additional information