The leakage current caused by the Si pileup at the regrowth interface of AlGaN/GaN high electron mobility transistors (HEMTs) is significantly suppressed by the semi-insulating Mg-doped GaN layer. Mg is unintentionally doped and can be originated from the graphite susceptor of metal organic vapor phase epitaxy. Before regrowth of the AlGaN/GaN heterostructure, the GaN template is treated with hydrochloric acid (HCl) and hydrogen peroxide/potassium hydroxide (H₂O₂/KOH) solution to promote the adsorption of Mg on the GaN surface. The Mg-doped GaN channel layer is highly resistive due to the passivation of hydrogen. The p–n junction formed by the weakly p-type Mg-doped GaN layer and the n-type Si pileup layer depletes the excess electrons at the regrowth interface. As a result, the off-state drain leakage current of the HEMT device can be decreased by two orders of magnitude at 40 V.

中文翻译：

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未激活的Mg掺杂GaN层抑制AlGaN / GaN HEMT中的再生长界面泄漏电流

半绝缘的掺Mg的GaN层可显着抑制AlGaN / GaN高电子迁移率晶体管（HEMT）的再生界面处Si堆积引起的泄漏电流。Mg是无意掺杂的，可以源自金属有机气相外延的石墨感受器。在重新生长AlGaN / GaN异质结构之前，先用盐酸（HCl）和过氧化氢/氢氧化钾（H ₂ O ₂/ KOH）溶液以促进Mg在GaN表面上的吸附。掺杂Mg的GaN沟道层由于氢的钝化而具有高电阻。由弱p型掺杂Mg的GaN层和n型Si堆积层形成的p–n结耗尽了再生长界面上的多余电子。结果，HEMT器件的截止状态漏极泄漏电流可以在40 V时降低两个数量级。