Low-temperature metalorganic chemical vapour deposition of AlN for surface passivation of GaAs

Abstract

Aluminium nitride (AlN) thin films have been grown by low‐temperature metalorganic chemical vapour deposition (MOCVD) to passivate GaAs. By utilizing hydrazine (N2H4), highly resistive amorphous‐like AlN films were obtained at growth temperatures around 400°C. At the AlN‐GaAs interface, three deep trap levels were found: 0.6 eV (DL1) and 0.9 eV (DL2) below the conduction band minimum and 0.5 eV (DL3) above the valence band maximum. The number of DL1 levels was reduced by preparing As‐dimer‐stabilised surfaces of GaAs. The capture cross‐sections and time constants of DL1–DL3 suggest that these levels originated from point defects, not from precipitates or disorder. Neither precipitation nor reaction was detectable by Auger electron spectroscopy after annealing at 900°C for 20 min, indicating that the AlN‐GaAs interfaces are thermally stable. These results demonstrate that these AlN films are applicable as capping films for processing GaAs as well as passivation films.

N-doped TiO2 coatings grown by atmospheric pressure MOCVD for visible light-induced photocatalytic activity

“…The substrates were placed on a stainless steel sample holder (3.2 cm in diameter) heated by HF induction [11]. For the N doping, hydrazine was used because it allows the formation of reactive nitrogen in the gas phase at relatively low temperature (150°C) [12] compared to NH 3 which requires temperature higher than 600°C. The typical experimental procedure is described in a companion paper [13].…”

Low Temperature Chemical Vapor Deposition of Titanium Nitride Thin Films with Hydrazine and Tetrakis(dimethylamido)titanium

“…Additional advantages of hydrazine compared to ammonia are its lower hydrogen to nitrogen ratio and its lower decomposition temperature (as low as 140°C). 30 The liquid precursors, tetrakis(dimethylamido)titanium (99%) and hydrazine (98%) were purchased from Strem Chemicals and Aldrich, respectively. These chemicals were handled in a dry nitrogen glove box.…”

“…34 Previous mass spectrometry data indicate that hydrazine begins to thermally decompose as low as 150°C. 30 Surface studies show that hydrazine can be used to cover a surface with -NH 2 groups at temperatures as low as 300 K. 35 This reduction mechanism can also be used to rationalize the variations in deposition rates among films made with hydrazine, ammonia, or mixed ammonia-hydrazine. Using hydrazine instead of ammonia enhances the deposition rate because hydrazine provides a lower temperature pathway for reduction of the titanium.…”

Особенности Спектрально-Разрешенной Термолюминесценции В Облученных Микрокристаллах Нитрида Алюминия

“…Известны применения AlN для создания светодиодов и устройств поверхностных акустических волн, подложек для элементов электроники, детекторных сред для регистрации ионизирующего излучения различной природы [8][9][10][11][12][13][14]. Кроме того, микро-и наноструктуры AlN используются для создания компактных устройств на базе микролазеров УФ и видимого диапазонов [8,[15][16][17][18].…”