Top-Gated P-MOSFET with CVD-Grown WSe<sub>2</sub> Channels via Self-Aligned WO<sub><i>x</i></sub> Conversion for Spacer Doping.

Li, Meng-Zhan; Hung, Terry Y T; Yun, Wei-Sheng; Sathaiya, D Mahaveer; Chou, Sui-An; Liew, San Lin; Yang, Ying-Mei; Lin, Kuang-I et al. · Nano Lett · 2025

basic_science · Level V

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Abstract

WO<sub><i>x</i></sub> conversion for doping is highlighted in recent advancements in WSe<sub>2</sub> p-FETs. While past studies focused on exfoliated WSe<sub>2</sub> flakes, our research examines CVD-grown WSe<sub>2</sub> films, assessing the impact of this doping on channel mobility and contact resistance in devices. Our approach enables effective threshold voltage tuning in both n- and p-type FETs with various low-dimensional material channels with the doping mechanism well captured by TCAD simulations. When applied to WSe<sub>2</sub>, trilayer devices exhibited a good and comparable median field-effect mobility of 65 cm<sup>2</sup>/V·s following the conversion process. Consequently, trilayer WSe<sub>2</sub> was used to demonstrate top-gated p-MOSFETs via self-aligned WO<sub><i>x</i></sub> conversion in the spacer region, achieving a 250-fold enhancement in the on-current while maintaining a subthreshold swing of 80 mV/dec. Our findings provide a comprehensive understanding of WO<sub><i>x</i></sub> conversion and its general applicability, paving the way for its use in future logic devices with low-dimensional materials.