Suppression of ALD-Induced Degradation of Ge MOS Interface Properties by Low Power Plasma Nitridation of GeO2

A high quality interfacial layer (IL) is important to realize advanced high-k/Ge gate stacks for Ge metal oxide semiconductor (MOS) devices. Here, GeO 2 can be regarded as one of the most promising interfacial layers (ILs). However, significant degradation of ultra thin GeO 2 IL after atomic layer deposition (ALD) of high- k films has been reported, making it difficult to integrate GeO 2 with high- k gate dielectrics. In this study, an in-situ plasma nitridation method is employed for plasma oxidized GeO 2 layers in order to realize GeO 2 -based ILs robust against ALD processes, resulting in a GeON layer with tunable nitrogen concentration. The impact of the nitrogen content on the properties of GeON IL is examined. It is found that the GeON IL with low nitrogen content exhibits good MOS interface properties, inherent to the GeO 2 /Ge interface, as well as its tolerance for ALD-induced damages.