Electrical properties of MgO/GaN metal-oxide-semiconductor structures
Electrical properties of MgO/GaN metal-oxide-semiconductor structures
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DOI：
10.1016/j.sse.2020.107881
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发表时间：
2020-10-01
影响因子：
1.7
通讯作者：
Tansu, Nelson
中科院分区：
文献类型：
--
作者：
Ogidi-Ekoko, Onoriode N.;Goodrich, Justin C.;Tansu, Nelson
采用原子层沉积法（ALD）在GaN上沉积MgO/Al 2 O3栅介质，测量了MOS电容器的电学性能。对于Al 2 O3（1 nm）/MgO（20 nm）介电层，MOS电容器在1V下测得的漏电流密度为0.25mA/cm（2）。从C-V测量中获得了类似于0.1 μ F/cm（2）的峰值电容，观察到了显著的滞后现象。此外，在450 ℃下15分钟的合成气体退火导致在1V下1A/cm（2）的漏电流密度增加，同时峰值电容也增加了约30%。为了改善性能，沉积Al 2 O3（20 nm）/MgO（20 nm）电介质叠层，其在1V下表现出类似于1 × 10（-5）mA/cm（2）的漏电流密度，这对应于比单层电介质的电流密度低4个数量级的电流密度。此外，3层Al 2 O3（10 nm）/MgO（20 nm）/Al 2 O3（10 nm）堆叠也显示出类似于4个数量级的漏电流密度降低，以及界面态密度降低，同时保持高k电介质。使用光辅助C-V方法估计3层堆叠的界面态密度在6.8 x 10（11）eV（-1）cm（-2）和1.5 x 10（12）eV（-1）cm（-2）之间。
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/cm(2) at 1 V was measured for the MOS capacitor. A peak capacitance of similar to 0.1 mu F/cm(2) was obtained from the C-V measurements with significant hysteresis observed. In addition, a 15-minute forming gas anneal at 450 degrees C resulted in an increased leakage current density of 1 A/cm(2) 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 similar to 1 x 10(-5) mA/cm(2) at 1 V, which corresponds to similar 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 similar to 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 10(11 )eV(-1) cm(-2) and 1.5 x 10(12) eV(-1) cm(-2) for the 3-layer stack using the photo-assisted C-V method.