Performance of molecular-beam epitaxy-grown midwave infrared HgCdTe detectors on four-inch Si substrates and the impact of defects

Abstract

We are continuing development of the growth of midwave infrared (MWIR) HgCdTe by molecular-beam epitaxy (MBE) on 4-in. Si substrates and the fabrication of state-of-the-art detectors and focal plane arrays (FPAs). Array formats of up to 2048 × 2048 and unit cells as small as 20 m have been made. We regularly measure response operability values in excess of 99% on these arrays. These values typically exceed expectations, with the number of outages corresponding to as-grown defect densities four times lower than what we measure. We have investigated this operability discrepancy and now can account for it. Comparisons of measured properties were used to establish trends between defect occurrence and pixel operability. These correlations show that a combination of defect removal and low-impact defects provide the explanation. Having this knowledge will allow for better operability predictions and assist in efforts to reduce defect impact on FPA performance.

Control and growth of middle wave infrared (MWIR) Hg(1−x)CdxTe on Si by molecular beam epitaxy

“…Effects of these de-fects on device performance have already been reported. 2,11 The mechanism of formation and cause of defects are very complex and diverse. Different authors and groups agree that voids and microvoids are directly related to Hg fluxes and substrate growth temperature.…”

“…The molecular beam epitaxy (MBE) HgCdTe/Si technology has proven the ability to produce FPAs, which indicates that Si substrates offer a viable solution for cost-effective largearea HgCdTe epitaxy. [1][2][3] Additionally, Si provides a robust substrate for processing and its thermalexpansion is matched to the Si readout integrated circuit. In this case, the thin CdTe buffer layer and HgCdTe active layers are constrained to the thick Si substrate.…”

Hg(1‐x)CdxTe from short to long wave infrared on Si substrates grown by MBE

“…Particulates, voids, and micro-voids are easily detected by optical microscopy. Effects of these defects on device performance have already been reported [5,6]. The mechanism of formation and cause of defects are very complex and diverse.…”

Flexibility of p–n Junction Formation from SWIR to LWIR Using MBE-Grown Hg(1–x)Cd x Te on Si Substrates

“…Effects of these defects on device performance have already been reported. 5,6 The mechanism of formation and cause of defects are very complex and diverse. Different authors and groups agree that voids and microvoids are directly related to Hg fluxes and substrate growth temperature.…”