Reducing the interface trap density in Al2O3/InP stacks by low-temperature thermal process

By applying low-temperature processes below 300 degrees C, high-performance Al/Al2O3/InP metal-insulator-semiconductor capacitors with low interface trap density and small capacitance frequency dispersion at the accumulation regime are demonstrated. A minimum interface trap density of 1.2 x 10(11) cm(-2) eV(-1) near the midgap is obtained. The impacts of thermal treatment on interface traps, thermal stability, and interfacial bonding configurations are studied and discussed. It is found that interface trap density could be significantly reduced by removing phosphorus and its oxides at low temperature (250-300 degrees C), while further increasing the thermal treatment temperature is harmful to interface quality. (C) 2015 The Japan Society of Applied Physics