Large format multi-wafer production of LWIR photodetector structures on 150mm GaSb substrates by MBE

Abstract

As GaSb based LWIR nBn detector structures have progressed from development into production, the standard substrates have been 76.2 and 100 mm in diameter. Additionally, production growths on 125 mm substrates are gaining popularity. To meet demands for larger focal plane arrays (FPA), improve throughput, volume, and yield, IQE has made the next step in this progression. Our first demonstration of multi-wafer growth of 150 mm GaSb exhibited uniform, high quality MWIR epitaxy. In this work, we will share our results for the more challenging GaSb-based LWIR nBn detector structures. These growths were carried out on a large format platen (7 × 150 mm) by Molecular Beam Epitaxy (MBE). The material properties as measured by AFM, HRXRD, Nomarski microscope, and PL, along with diode performance (turn-on, QE, cutoff wavelength), will be presented. Using this data, we will analyze the wafer-to-wafer cross-platen uniformity. Additionally, we will compare the characterization and device results to similar structures grown on smaller diameter substrates, and consider the viability of utilizing 150 mm GaSb substrates for LWIR nBn detector structures.