RF Enhancement-Mode -GaN Gate HEMT on 200 mm-Si Substrates

Enhancement-mode (E-mode) submicron 0.45- $\mu \text{m}~{p}$ -GaN gate HEMTs on 200-mm high-resistivity-Si (HRS) substrates have been demonstrated with high uniformity and high overall combined performance for RF applications. The ${p}$ -GaN gate HEMT exhibits a positive threshold voltage ( ${V}_{\text {TH}}$ ) of +0.58 V at ${I}_{\text {D}}$ of 0.1 mA/mm, a peak transconductance ( ${G}_{\text {M}}$ ) of 150 mS/mm, high saturation current density of 630 mA/mm at a gate bias ( $V_{\text {GS}}$ ) of 6 V and >1 A/mm at a ${V}_{\text {GS}}$ of 11 V. A low OFF state leakage current of $1.5~\mu $ A/mm is obtained at a ${V}_{\text {DS}}$ of 48 V with a forward OFF-state breakdown voltage larger than 65 V. The device exhibits a current gain cut-off frequency ${f}_{\text {T}}$ of 22.4 GHz, and a power gain cut-off frequency ${f}_{\text {MAX}}$ of 45.3 GHz. At 5 GHz, large-signal load-pull measurement yields an output power density of 1.4 W/mm and a power added efficiency up to 55.4 % with a drain voltage less than 20 V.