Improved voltage gain of transimpedance amplifier by AlGaAs/InGaAs doped-channel FET's

AlGaAs/InGaAs doped-channel FET's were investigated, and were utilized for transimpedance (TZ) amplifier circuits. Due to a high current density, a high gain linearity, and high gate breakdown and turn-on voltages of device characteristics, the AlGaAs/InGaAs doped-channel FET is shown to increase the noise margins and voltage gain in a buffered FET logic (BFL) inverter circuit, as compared with the circuit performance built by GaAs MESFET's. This amplifier also improves transimpedance gain, dynamic signal level, and the 3-dB frequency bandwidth. The transimpedance gain-bandwidth product (Z/sub T//spl middot/BW) is 17 GHz/spl middot/k/spl Omega/, which is much higher than in previous published reports.