The low leakage current in floating body GaN metal oxide semiconductor field effect transistors

Wide bandgap semiconductor based metal oxide semiconductor field effect transistors (MOSFETs) with an embedded p-type body layer (i.e., without grounding p-type body) was theoretically analyzed. In the GaN system, the reverse bias current density at the off-state, under applied 600 V at reverse bias region, was negligibly as small as 2.03 × 10−8 A/cm2, even at the high temperature, 600 K. As a result, the variation in the potential of p-type layer was 0.26–0.52 V in the range of 300–600 K, i.e., negligible compared with the built-in voltage of the pn-junction (∼3.04–3.27 V ≈ bandgap energy in the range of 300–600 K). It is distinct consequence from cases of Si transistors, where the potential variation and leakage current were significant. This unique nature of wide bandgap material enables us to remove the contact to ground p-layer, which is beneficial in reducing device size, and thus on-resistance, significantly.