用MOVPE和RF-MBE方法极性控制生长GaN(英文)

Polarity-controlled Growth of GaN by MOVPE and RF-MBE

本文报道了用低压ＭＯＶＰＥ和ＲＦ－分子束外延法在蓝宝石衬底上作极性控制的ＧａＮ生长。以“双Ａｌ单层”模型讨论了用ＭＯＶＰＥ和ＭＢＥ法在蓝宝石衬底上生长ＧａＮ的极性选择的机理，并对ＡｌＮ在极性转换过程中的作用给出了适当的解释。通过极性控制的生长，使ＭＢＥ法生长的ＧａＮ的表面形貌和电学特性都得到了改善；并对ＬＰ－ＭＯＶＰＥ生长开发出了一种“三步生长法”，这样就可以用更多的外延方式在蓝宝石衬底上生长出高质量的ＧａＮ膜。

In the present work, the polarity-controlled growth of GaN on sapphire substrate by LP-MOVPE and RF-MBE is demonstrated. The mechanisms for polarity selection of GaN on sapphire substrate both in MOVPE and MBE growth are discussed based on the 'two monolayers of Al' model, which also gives a reasonable explanation to the polarity reversion mechanism by AlN. Through the polarity-controlled growth, surface morphology and electrical property of GaN grown by RF-MBE is improved; a three-step growth method is developed for LP-MOVPE, so that high quality GaN films can be obtained in a more epitaxial way on sapphire substrate.