Significant suppression of surface leakage in GaSb/AlAsSb heterostructure with Al₂O₃ passivation

Abstract

This work develops a (NH4)2S/Al2O3 passivation technique for photodiode-basedGaSb/AlAsSb heterostructure. Surface-sulfurated GaSb/AlAsSb heterostructure mesas show a significant suppression of reversed-bias dark current by 4 -5 orders of magnitude after they are further passivated by Al2O3 layers. So the mesa sidewalls treated with (NH4)2S/Al2O3 layers can effectively inhibit the shunt path of dark carriers. The activation energies for both bulk and surface components are extracted from temperature-dependent current-voltage characteristics, which suggest that the bulk characteristics remain unchanged, while Fermi-level pinning at surfaces is alleviated. Additionally, temperature coefficients of the breakdown voltage are extracted, confirming that the breakdown process is confined entirely in the large bandgap AlAsSb regions. This study shows that the implementation of (NH4)2S/Al2O3 passivation can lead to room-temperature GaSb-based photodiodes and GaSb/AlAsSb-based avalanche photodiodes for highly efficient photodetection..

Optimization of surface passivation for suppressing leakage current in GaSb PIN devices

“…Similar phenomena can be hypothesized for GaSb passivation as well, where the Al-O interfacially bonds through either supplementing or substituting Sulfur terminated bonds further decreasing surface leakage current. [28][29][30] More importantly, after measuring the device 30 days later, the leakage current remains the same as that after passivation, suggesting that the encapsulating layer can effectively inhibit the desorption of sulfur atoms. Figure 3-3(b) shows significant increase in surface resistivity after passivation.…”

Модификация Атомной И Электронной Структуры Поверхности Полупроводников А-=sup=-Iii-=/Sup=-В-=sup=-v-=/Sup=- На Границе С Растворами Электролитов О Б З Ор

“…Конструкция поглощающей i-области может различаться в зависимости от рабочего диапазона длин волн. В частности, это может быть одиночный слабо легированный слой [202,358,359], гетероструктура [360] или сверхрешетка второго рода (например, GaSb/InAs), в которой валентная зона одного слоя перекрывается с зоной проводимости соседнего слоя [21,353,361].…”

“…Все эти приборы эффективно работают, как правило, при криогенных температурах. Недавно, однако, было установлено, что пассивация фотодиодной гетероструктуры GaSb/AlAsSb водным раствором сульфида аммония с последующим нанесением защитного слоя Al 2 O 3 позволила добиться эффективной работы фотодиода при комнатной температуре, в том числе в режиме лавинного умножения [360].…”

“…Кроме того, этот метод универсален и может использоваться для модификации поверхности любых полупроводников А III В V и их твердых растворов. В настоящее время обработка растворами электролитов позволяет осуществлять эффективную модификацию наноструктур [296,388], интерфейсов [344] и приборов на основе гетероструктур [360,377].…”

Passivation Strategies for Enhancing Solution-Gated Carbon Nanotube Field-Effect Transistor Biosensing Performance and Stability in Ionic Solutions

“…Unfortunately, the discussion of leakage currents is one that has been underreported in the BioFET space. While the issue of parasitic currents in transistors operating in air (or non-liquid-gated devices) is well documented, with several examples of passivation-focused studies aimed at minimizing these artifact currents, − the same discussion of gate leakage mitigation strategies is one that has been missing from the solution-gated transistor space. Several reports have discussed the importance of leakage current reduction in these devices, ,, as well as called for the reporting of leakage currents in relevant applications, but a consistent and reliable encapsulation strategy to overcome the issue remains unclear.…”