Thermal activation of a Mg-doped GaN layer with a thin AlGaN capping layer was investigated by means of systematic electrical characterization. Two-dimensional electron gas generated at the AlGaN/GaN interface greatly inhibited activation of the underlying Mg-doped GaN layer. This finding is attributed to the charge states of the interstitial hydrogen atoms being released from the Mg–H complexes and their diffusivity being dependent on the Fermi level position in GaN-based heterostructures. Reasonable electrically active acceptor concentration in Mg-doped GaN was achieved by designing a hydrogen desorption pathway.

中文翻译：

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由薄 AlGaN 覆盖层引起的 p 型 GaN 中 Mg 活化的抑制和设计氢解吸路径的影响

通过系统电学表征研究了具有薄 AlGaN 覆盖层的 Mg 掺杂 GaN 层的热活化。在 AlGaN/GaN 界面产生的二维电子气极大地抑制了下面掺杂 Mg 的 GaN 层的激活。这一发现归因于从 Mg-H 复合物释放的间隙氢原子的电荷态及其扩散率取决于 GaN 基异质结构中的费米能级位置。通过设计氢解吸途径，实现了掺杂 Mg 的 GaN 中合理的电活性受主浓度。