Depletion/enhancement-mode β-Ga2O3 on insulator field-effect transistors with drain currents exceeding 1.5/1.0 A/mm

摘要

Recently, β-GaO has shown its great promise for next generation high power device applications due to its ultra-wide bandgap of 4.6-4.9 eV [1]-[5]. Despite the very early development stage, β-GaO metal-oxide-semiconductor field-effect transistors (MOSFETs) have demonstrated a high blocking voltage of 0.75 kV and a breakdown field of 3.8 MV/cm [2][4]. However, a crucial disadvantage of this material is its low thermal conductivity of 0.1-0.3 W/cm-K. One of the approaches to solve this issue is to introduce a high thermal conductivity substrate with β-GaO on insulator (GOOI) structure rather than the β-GaO native substrate. It is questionable whether β-GaO based FETs can compete with existing GaN or SiC technologies in terms of drain current (I) and on-resistance (R). Meanwhile, whether β-GaO can also be applied in large-signal RF power devices remains to be answered, although β-GaO suffers from relatively low electron mobility (μ). In this abstract, we have fully explored the device potentials and demonstrated that depletion/enhancement (D/E)-mode GOOI FETs can achieve a record high I of 1.5/1.0 A/mm and high estimated virtual source velocity v=7.3 × 10 cm/s.