Top-Gated P-MOSFET with CVD-Grown WSe₂ Channels via Self-Aligned WO Conversion for Spacer Doping.

Area of Science:

• Materials Science
• Nanotechnology
• Semiconductor Device Physics

Background:

• Tungsten diselenide (WSe2) field-effect transistors (FETs) are crucial for next-generation electronics.
• Previous doping strategies often relied on exfoliated WSe2 flakes, limiting scalability.
• Understanding doping effects on channel mobility and contact resistance in CVD-grown WSe2 is essential.

Purpose of the Study:

• To investigate tungsten oxide (WO) conversion as a doping method for CVD-grown WSe2 films.
• To assess the impact of WO conversion doping on device performance, including mobility and resistance.
• To demonstrate the general applicability of WO conversion for tuning threshold voltage in various low-dimensional FETs.

Main Methods:

• Utilized chemical vapor deposition (CVD) to grow WSe2 films.
• Applied WO conversion for doping WSe2 devices.
• Employed Technology Computer-Aided Design (TCAD) simulations to model the doping mechanism.

Main Results:

• Trilayer WSe2 devices achieved a median field-effect mobility of 65 cm²/V·s after WO conversion.
• Demonstrated top-gated p-type metal-oxide-semiconductor field-effect transistors (p-MOSFETs) using self-aligned WO conversion.
• Achieved a 250-fold enhancement in on-current with a subthreshold swing of 80 mV/dec in WSe2 p-MOSFETs.

Conclusions:

• WO conversion is an effective doping technique for CVD-grown WSe2, improving device performance.
• The method allows for precise threshold voltage tuning in both n-type and p-type FETs.
• This approach offers a viable pathway for developing future logic devices utilizing low-dimensional materials.