High-Quality Interface in Al2O3/GaN/AlGaN/GaN MIS Structures With In Situ Pre-Gate Plasma Nitridation

We report an in situ low-damage pre-gate treatment technology in an atomic layer deposition (ALD) system prior to the ALD-Al2O3 deposition, to realize high-quality Al2O3/III-nitride (III-N) interface. The technology effectively removes the poor quality native oxide on the III-N surface while forming an ultrathin monocrystal-like nitridation interlayer (NIL) between Al2O3 and III-N surface. With the pre-gate treatment technology, high-performance Al2O3(NIL)/GaN/AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistors are demonstrated, exhibiting well-behaved electrical characteristics including suppressed gate leakage current, a small subthreshold slope of similar to 64 mV/dec, and a small hysteresis of similar to 0.09 V.