Strained-channel Si n-MOSFET with GaN-drain via dual-step selective epitaxy for mobility enhancement on Si(100) substrate

This work explores the integration of strained-channel silicon n-MOSFET with GaN drain using the dual-step selective area epitaxial growth of GaN process, enabling CMOS-compatible, fully selective GaN growth with an excellent GaN/Si interface while adopting a GaN-drain-first manufacturing strategy to accommodate thermal budget constraints. After GaN growth and device fabrication, the Si n-MOSFET with a GaN drain exhibited a strained channel, as the epitaxial GaN acts as a stressor, inducing tensile strain in silicon near the GaN drain and enhancing the device’s low-field mobility. Atomic-resolution scanning transmission electron microscopy with strain mapping confirmed the strain effects, while electrical measurements demonstrated a mobility enhancement from 103.8 to 119.8 cm2 V−1 s−1. The integrated GaN drain offers a high breakdown electric field and excellent optoelectronic properties, making it highly promising for high-power and high-frequency system-on-chip technologies, as well as for integration with laser diodes as a drain. These findings highlight the strong potential of GaN-drain Si n-MOSFETs for radio-frequency power amplifier applications and pave the way for advancements in radar, radio, and optoelectronic circuits and systems.