Influence of Pixel Etching on Electrical and Electro-Optical Performances of a Ga-Free InAs/InAsSb T2SL Barrier Photodetector for Mid-Wave Infrared Imaging

Abstract

In this paper, the influence of etching depth on the dark current and photo-response of a mid-wave infrared Ga-free T2SL XBn pixel detector is investigated. Two wet chemical etching depths have been considered for the fabrication of a non-passivated individual pixel detector having a cut-off wavelength of 5 µm at 150 K. This study shows the strong influence of the lateral diffusion length of a shallow-etched pixel on the electro-optical properties of the device. The lowest dark current density was recorded for the deep-etched detector, on the order of 1 × 10−5 A/cm2 at 150 K and a bias operation equal to −400 mV. The corresponding quantum efficiency was measured at 60% (without anti-reflection coating) for a 3 µm thick absorbing layer. A comparison of experimental results obtained on the two kinds of etched pixels demonstrates the need for a deep-etching process combined with efficient passivation for FPA manufacturing.

Electro-optical characterizations to study minority carrier transport in Ga-free InAs/InAsSb T2SL XBn midwave infrared photodetector

“…In the temperature range 110K-150K, the GR regime is identified which indicates that a depletion region is formed at the absorber-barrier interface and extends into the absorber, since it is the less targeted doped region between the two. 12 The -0.4V dark current density at 150K is 4.5 × 10 5 A/cm 2 which is approximately 10 times the Rule07. 21 Figure 5 shows the experimental QE of the device in temperature range [90K-220K] and under two applied biases V = −0.2V & −0.4V .…”

Two-step etch in n-on-p type-II superlattices for surface leakage reduction in mid-wave infrared megapixel detectors

“…The strong surface degradation observed in n-on-p devices is attributed to that the p-n junction is being more exposed during the etching process compared to p-on-n devices when the barrier is positioned below the absorber [19][20][21]. This makes the fabrication of detectors with n-onp polarities (with p-type absorbers) challenging.…”

“…Finally, by design, the p-n junction of the photodiodes can be placed on the top of the absorber. In this configuration, the diodes can be isolated by a shallow mesa etch [21,22], which minimizes the surface exposed. Planar-or shallow-etched detectors reduce the surface leakage and do not compromise the active area fill factor; however, the lateral transport of carriers can result in electrical cross talk between pixels [21][22][23].…”

“…In this configuration, the diodes can be isolated by a shallow mesa etch [21,22], which minimizes the surface exposed. Planar-or shallow-etched detectors reduce the surface leakage and do not compromise the active area fill factor; however, the lateral transport of carriers can result in electrical cross talk between pixels [21][22][23]. The lateral diffusion length is an intrinsic characteristic of the material, but its effect on the total carrier collection increases as the diodes become smaller.…”

Facile and Electrically Reliable Electroplated Gold Contacts to p-Type InAsSb Bulk-Like Epilayers

“…The MIR photodetectors find considerable technological importance in medical diagnostics, IR imaging, environmental monitoring and chemical sensing [3][4][5][6]. Recently, InAsSb-based detector technology has been extended to the development of photodiodes with a variety of configurations such as n-i-p structure [3,4] or to the XBn barrier structures [7].…”