High-breakdown voltage field-plated normally-off AlGaN/GaN HEMTs for power management

The high breakdown voltage AlGaN/GaN HEMTs with source-terminated field plate was firstly fabricated for high frequency and high power application, employing by CF₄ plasma treatment for enhancement-mode (E-mode). The results showed that by adding the distance of gate to drain, L_GD from 5 um to 15um, the breakdown voltage of the device was rapidly increased 350V, whose value is from 50V to 400V while the threshold voltage of the device, V_TH was +0.5V by the charge modulation technology of CF₄ plasma. When the distance of source-terminated field plate, L_FP was about 3um, the breakdown voltage of the device was apparently improved because the electric field near the gate edge was effectively shielded. The breakdown voltage and the specific on-resistance for the L_GD and L_FP distance of the device about 15um and 3um were about 475V and about 2.9 m Ω · cm² respectively. The results from RF measurement showed that with the variation of V_GS, the f_T and f_MAX parameters of the device with source-terminated field plate were the order of Gigahertz frequency. The DC, AC and transient characteristics of E-mode Power AlGaN/GaN HEMTs were satisfied and its forward current was about 90 mA. Therefore the E-mode AlGaN/GaN HEMTs was very suitable as the novel power switch technology in energy management application.