Submicrometer Process and RF Operation of InAs Quantum Hot-Electron Transistors

The fabrication process of a hot-electron unipolar transistor with vertical transport based on InAs material is reported. Devices with an emitter width of 0.3 μm are fabricated and characterized. This submicrometer geometry allowed suppressing parasitic resistances and achieving high-current densities required for high-frequency operation. For the first time, for a hot-electron transistor, RF performances were achieved at room temperature. Cutoff frequencies of f_t = 75 GHz and f_max = 88 GHz were obtained on devices transferred on an insulating substrate.