Exploring Breakdown Voltage Improvement in 20-nm InGaAs-Channel HEMT-OI with Metallic Back-Gate

We report on a $20-\mathrm{nm}$ gate length Quantum-Well High-Electron-Mobility Transistor (HEMT) on a Silicon Sub strate with an InGaAs channel. A back-gated metallic field-plate, connected to the buffer backside, is used to provide dynamic threshold and breakdown voltages. After calibrating TCAD simulations against experimental results, we explored the possibility of enhancing the transistor breakdown voltage by varying the geometric parameters of the back-gate as well as the cap layer concentration. Our findings indicate that increasing the back-gate length relative to the middle of the front gate can enhance the HEMT breakdown voltage by over 10%. Reducing the cap layer concentration or removing the cap layer, in addition to the presence of the back-gate, can drastically improve both the output conduction and the breakdown voltage by over 1 V compared to the reference. This study opens up the possibility for new analog and RF designs utilizing this back-gate.