Demonstration of MOCVD-Grown Long-Wavelength Infrared InAs/GaSb Superlattice Focal Plane Array

Yan Teng,Xiujun Hao,Ming Liu,Weirong Xing,Baile Chen,Zhuo Deng,Jiafeng Liu,Meng Li,Hong Zhu,Yunlong Huai,He Zhu,Yong Huang

doi:10.1109/access.2021.3072845

Abstract

High-performance InAs/GaSb type-II superlattice infrared detectors and focal plane arrays (FPAs) are normally grown by molecular beam epitaxy (MBE). In this work, we demonstrate the first long-wavelength infrared InAs/GaSb superlattice FPA grown by metalorganic chemical vapor deposition (MOCVD) with clear image. High-quality superlattice material was obtained evidenced by sharp X-ray diffraction peaks and atomic flat surface. Electrical and optical measurements performed on single element detectors showed a 50% cut-off wavelength of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim 10.1~\mu \text{m}$ </tex-math></inline-formula> , a dark current density of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2.5\times 10^{-5}$ </tex-math></inline-formula> A/cm 2 , a peak responsivity of 0.88 A/W and a peak detectivity of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.7\times 10^{11}$ </tex-math></inline-formula> cm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\cdot $ </tex-math></inline-formula> Hz 1/2 /W at 80 K. A <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$320\times256$ </tex-math></inline-formula> FPA with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$30~\mu \text{m}$ </tex-math></inline-formula> pixel pitch was then fabricated. With an integration time of 1.9 ms and an applied bias of -0.1 V, the FPA shows an average operability of 96.96%, a non-uniformity of 4.97%, a noise equivalent temperature difference of 51.1 mK and a peak detectivity of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2.3\times 10^{10}$ </tex-math></inline-formula> cm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\cdot $ </tex-math></inline-formula> Hz 1/2 /W at 80 K without thinning down the substrate.

Highlights

Long-wavelength infrared (LWIR) focal plane arrays (FPAs) with 50% cut-off wavelength of 8 to 12 μm have broad applications in diagnosis assistance, industrial process monitoring, and night vision
Compared to the dominant HgCdTe technology used in LWIR detection, InAs/GaSb type-II superlattices (T2SLs) have the merits of low Auger recombination rate [1], good material uniformity [2] and low fabrication cost [3]
We demonstrate a metalorganic chemical vapor deposition (MOCVD)-grown LWIR T2SL single detector and FPA at a cut-off wavelength of around 10 μm

Summary

INTRODUCTION

Long-wavelength infrared (LWIR) focal plane arrays (FPAs) with 50% cut-off wavelength of 8 to 12 μm have broad applications in diagnosis assistance, industrial process monitoring, and night vision. Y. Teng et al.: Demonstration of MOCVD-Grown LWIR InAs/GaSb Superlattice FPA high-performance LWIR detectors with Al-free single heterojunction structure named ‘‘PNn’’ [16], [17]. In the PNn structure, the space charge region is only confined in the mid-wavelength barrier layer and LWIR absorber remains a flat band condition., which reduces the generationrecombination (G-R) and tunneling current. This structure can be exploited to realize bias-selectable dualband detection [18]. We demonstrate a MOCVD-grown LWIR T2SL single detector and FPA at a cut-off wavelength of around 10 μm. To the best of our knowledge, this is the first antimonide-based LWIR FPA demonstrated by MOCVD

MATERIALS GROWTH AND CHARACTERIZATION

CONCLUSION