We report on a method for controlling the polarity of gallium nitride (GaN) using an E-beam evaporated aluminum (Al) layer on a sapphire substrate. A high-temperature nitridation process was designed to enable the amorphous Al layer to serve as a nucleation layer for single-crystal Ga-polar GaN growth. The Al layer also acts as a mask that prevents N-polar GaN growth. As a result, Ga-polar and N-polar GaN can be grown on the Al layer and sapphire surface, respectively. This method is not only advantageous for the selective polarity control but also to simplify the fabrication process of lateral polarity structures.

中文翻译：

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使用电子束蒸发铝层的单晶GaN生长和极性控制

我们报告了一种在蓝宝石衬底上使用电子束蒸发的铝（Al）层控制氮化镓（GaN）极性的方法。设计了高温氮化工艺，以使非晶Al层可以用作单晶Ga极性GaN生长的成核层。Al层还充当防止N极性GaN生长的掩模。结果，可以分别在Al层和蓝宝石表面上生长Ga-极性和N-极性的GaN。该方法不仅有利于选择性极性控制，而且简化了横向极性结构的制造工艺。