Low-temperature plasma enhanced atomic layer deposition of large area HfS<sub>2</sub> nanocrystal thin films*
Ailing Chang, Yichen Mao, Zhiwei Huang, Haiyang Hong, Jianfang Xu, Wei Huang, Songyan Chen, Cheng Li
Abstract
Hafnium disulfide (HfS 2 ) is a promising two-dimensional material for scaling electronic devices due to its higher carrier mobility, in which the combination of two-dimensional materials with traditional semiconductors in the framework of CMOS-compatible technology is necessary. We reported on the deposition of HfS 2 nanocrystals by remote plasma enhanced atomic layer deposition at low temperature using Hf(N(CH 3 )(C 2 H 5 )) 4 and H 2 S as the reaction precursors. Self-limiting reaction behavior was observed at the deposition temperatures ranging from 150 °C to 350 °C, and the film thickness increased linearly with the growth cycles. The uniform HfS 2 nanocrystal thin films were obtained with the size of nanocrystal grain up to 27 nm. It was demonstrated that higher deposition temperature could enlarge the grain size and improve the HfS 2 crystallinity, while causing crystallization of the mixed HfO 2 above 450 °C. These results suggested that atomic layer deposition is a low-temperature route to synthesize high quality HfS 2 nanocrystals for electronic device or electrochemical applications.