Formation of device-quality metal–insulator–semiconductor structures with oxide–nitride–oxide dielectrics by low-temperature plasma-assisted processing, combined with high-temperature rapid thermal annealing

Abstract

The formation of oxide–nitride–oxide (ONO) dielectrics on crystalline Si substrates by low-temperature plasma-assisted oxidation and remote plasma-enhanced chemical-vapor deposition (PECVD) is described. The electrical performance of the ONO dielectrics has been correlated with (i) the chemical bonding within the nitride layers, (ii) the accumulation of N atoms at the SiO2/Si interface, and (iii) the formation of oxynitride interfacial regions internal to the ONO structure. The ONO dielectrics have been studied in metal-insulator-semiconductor (MIS) devices, and their electrical properties have been examined by capacitance–voltage (C–V), and current–voltage (I–V) measurements. A post-deposition rapid thermal anneal (RTA) for 30 s at 900 °C, has been shown to reduce (i) the fixed charge at the two internal oxide/nitride (O/N) interfaces and (ii) the density of traps Dit at the SiO2/Si interface.