Top-Gated P-MOSFET with CVD-Grown WSe₂ Channels via Self-Aligned WO_<i>x</i> Conversion for Spacer Doping

WO_<i>x</i> conversion for doping is highlighted in recent advancements in WSe₂ p-FETs. While past studies focused on exfoliated WSe₂ flakes, our research examines CVD-grown WSe₂ 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 WSe₂, trilayer devices exhibited a good and comparable median field-effect mobility of 65 cm²/V·s following the conversion process. Consequently, trilayer WSe₂ was used to demonstrate top-gated p-MOSFETs via self-aligned WO_<i>x</i> 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_<i>x</i> conversion and its general applicability, paving the way for its use in future logic devices with low-dimensional materials.