Electrical properties of metal-oxide-semiconductor (MOS) capacitors were measured with MgO / Al₂O₃ gate dielectrics deposited by atomic layer deposition (ALD) on GaN. For an Al₂O₃ (1 nm) / MgO (20 nm) dielectric layer, a leakage current density of 0.25 mA/cm² at 1 V was measured for the MOS capacitor. A peak capacitance of ∼0.1 μF/cm² was obtained from the C-V measurements with significant hysteresis observed. In addition, a 15-minute forming gas anneal at 450 °C resulted in an increased leakage current density of 1 A/cm² at 1 V while also increasing the peak capacitance by approximately 30%. To improve the performance, an Al₂O₃ (20 nm) / MgO (20 nm) dielectric stack was deposited that exhibited a leakage current density of ∼1 x 10^-5 mA/cm² at 1 V, which corresponds to ∼4 orders of magnitude lower current density than that of the single layer dielectric. Additionally, a 3-layer Al₂O₃ (10 nm) / MgO (20 nm) / Al₂O₃ (10 nm) stack also shows a leakage current density reduction of ∼4 orders of magnitude, and a reduced density of interface states while remaining a high-k dielectric. The density of interface states was estimated to be between 6.8 x 10¹¹ eV^-1cm^-2 and 1.5 x 10¹² eV^-1cm^-2 for the 3-layer stack using the photo-assisted C-V method.

通过在GaN上通过原子层沉积（ALD）沉积的MgO / Al ₂ O ₃栅极电介质来测量金属氧化物半导体（MOS）电容器的电性能。对于Al ₂ O ₃（1nm）/ MgO（20nm）介电层，对于MOS电容器，在1V下测得的漏电流密度为0.25mA / cm ²。从CV测量获得的峰值电容为〜0.1μF/ cm ²，观察到明显的滞后现象。另外，在450°C下进行15分钟的成型气体退火会导致在1 V时泄漏电流密度增加到1 A / cm ²，同时还将峰值电容提高大约30％。为了提高性能，Al ₂ O沉积₃（20 nm）/ MgO（20 nm）电介质叠层，在1 V电压下的漏电流密度为〜1 x 10 ^-5 mA / cm ²，这比漏电流密度低约4个数量级。单层电介质。此外，三层Al ₂ O ₃（10 nm）/ MgO（20 nm）/ Al ₂ O ₃（10 nm）叠层还显示出泄漏电流密度降低了约4个数量级，并且界面密度降低了保持高k电介质状态。界面态的密度估计在6.8 x 10 ¹¹ eV ^-1 cm ^-2和1.5 x 10 ¹² eV ^-1之间使用光辅助CV方法的3层堆栈的cm ^-2。