Low Static and Dynamic On-Resistance with High Figure of Merit in AlGaN/GaN High Electron Mobility Transistors on Chemical Vapor Deposited Diamond

摘要

AlGaN/GaN high electron mobility transistors (HEMTs) on chemical vapor deposited (CVD) diamond with different gate–drain spacings (Lgd) are fabricated, and off-state breakdown voltage (BV_(gd)) along with a dynamic specific on-resistance (Dyn.-R_(on,sp)) is measured. R_(on,sp) is obtained in the range of 0.32–0.98 mΩ cm~2 for HEMTs with Lgd of 2–8 μm. The HEMTs exhibit a BV_(gd) of 415 V (L_(gd) = 8 μm) with a maximum lateral breakdown strength of 0.72MV cm~(-1). The power device figure of merit (FOM) of ≈0.18 GWcm~(-2) is obtained from HEMTs with Lgd of 8 μm. The HEMTs exhibit about 60% of higher FOM when compared with the reported HEMTs on CVD diamond (≈0.11 GW cm~(-2)). This is mainly due to the improvement of Ron,sp through the reduction of contact resistance (Rc) and sheet resistance (Rsh). The Dyn.-Ron,sp is estimated from pulsed (pulse width/period = 200 ns/1ms) I_D–V_D characteristics, which is comparable with the static R_(on,sp). These improved results of the fabricated AlGaN/GaN HEMTs on CVD diamond make it a promising candidate for high-voltage power switching device applications.