Structural and optical properties of GaAs(001) surfaces thermally annealed in dry N2 atmosphere

Abstract

Thermal annealing behaviors of GaAs͑001͒ surfaces in dry N 2 atmosphere have been studied by using spectroscopic ellipsometry ͑SE͒, optical microscopy, scanning electron microscopy, ex situ atomic force microscopy ͑AFM͒, x-ray photoelectron spectroscopy ͑XPS͒, and photoluminescence ͑PL͒ techniques. The SE data indicate that thermal annealing at temperatures T below 500°C causes no or a little influence on the surface morphology. Microscopic roughening starts to occur at T Ͼ 600°C and exhibits a saturated roughness value at ϳ800°C. AFM observation confirms the presence of a microscopically roughened surface overlayer after annealing at T ϳ 600-750°C and a macroscopically roughened overlayer at above 700°C. The XPS data indicate the removal of As 2 O 3 oxide after annealing at above 500°C; however, the Ga 2 O 3 oxide is always observed regardless of annealing temperature, although its peak intensity becomes remarkably large at T ϳ 700°C and small at T Ն 800°C. Annealing at T = 1000°C leads to deliquesced sample surface. The native GaAs oxide is also found to act as a passivation film against annealing-induced PL degradation for T below ϳ400°C.

Chemical Composition of Native Oxide Layers on In+Implanted and Thermally Annealed GaAs

“…It was found that arsenic atoms concentration also decreases during thermal annealing, the same results were described in [17]. Any arsenic oxides that may be formed via this elemental arsenic diusion to the surface are likely to be highly unstable and therefore easily evaporate.…”

Enhancement of photoluminescence efficiency from GaN(0001) by surface treatments

“…However, the effects of semiconductor surfaces on their luminescent properties have received little attention. Although a few reports showed the surface conditions affecting their luminescent properties, 3,4) no clear or conclusive evidence has been presented, yet to our knowledge. In order to improve the intensity of GaN LEDs, we should focus on the surface effects on the luminescence efficiency.…”

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

“…Чистая поверхность необходима для последующего проведения различных процессов эпитаксиального выращивания и нанесения диэлектрических покрытий. Основной проблемой является высокая термическая устойчивость оксидов атомов III группы, что не позволяет эффективно использовать отжиг в вакууме для очистки поверхности полупроводников [91][92][93]. Ионное распыление и различные методы " сухого" травления приводят, как правило, к существенному разупорядочиванию поверхности и к появлению большого количества дефектов, а в случае твердых растворов и к значительному изменению состава и, как следствие, объемных свойств полупроводника [26,27].…”