GaN on Si RF performance with different AlGaN back barrier

In this paper, the DC and RF device performance of AlGaN/GaN high-electron-mobility transistors (HEMTs) with different AlGaN back barrier thickness has been studied. The test results of the HEMTs with 50 nm back barrier exhibit $\mathrm{I}_{\text{ds},\text{sat}}=640\ \text{mA}/\text{mm},\ \text{gm}=405\ \text{mS}/\text{mm}$ , and on/off ratio = $1.5\mathrm{E}+04$ . In small-signal operation, cut-off frequency $\mathrm{F}_{\mathrm{T}}/\mathrm{F}_{\text{MAX}}=59/127\ \text{GHz}$ are achieved, which gives a high value of $(\mathrm{F}_{\mathrm{T}}\times\mathrm{L}_{\mathrm{g}})=14.7\ \text{GHz}\times\mu\mathrm{m}$ among the reported GaN-on-Si devices.