Submicron GaAs vertical electron transistor

To achieve high frequency performance in a transistor, along with low parasitics, the intrinsic device should have very low transit time of carriers from source to the drain. We report on the fabrication and D.C. characterization of vertical transistors with 0.5\microm drain to source spacing and with sub-\microm channel widths. A gmof 81 mS/mm was achieved in the devices doped at5 \times 10^{16}cm^-3and 47 mS/mm in those doped at7 \times 10^{15}cm^-3. We propose this structure as a convenient method of studying the influence of near-ballistic electron motion on transistor performance.