Atomic Layer Deposition of high-k oxides on InAlN/GaN-based materials

We demonstrate the applicability of atomic layer deposition of Al2O3 and ZrO2 on InAlN/GaN-materials by means of Metal Oxide Semiconductor High Electron Mobility Transistors (MOS-HEMTs). We investigate the impact of various surface pre-treatment methods, as well as the impact of in-situ pre-treatment by ALD on the electrical characteristics to evaluate insulation quality and thermal stability of the gate oxide stack, threshold voltage and interface traps. We show that by using the right surface pre-treatment as well as by using an adapted ALD pulsing scheme, one can obtain clearly improved MOS-HEMT performance concerning reduced gate leakage currents, suppressed current collapse effects, and increased drain currents