Microwave noise properties for resonant tunneling transistors (RTTs)

We propose and demonstrate a low noise amplifier utilizing the negative input conductance of resonant-tunneling transistors (RTTs). The fabricated RTTs, which integrate a resonant-tunneling diode (RTD) into the source of a heterojunction FET (HJFET), exhibited a negative input conductance at low frequencies (⩽10 GHz). When the gate bias is close to the resonance peak not only F_min but also R_n increases at low frequencies. Also, F_min shows a sharp dip at the valley current these behaviors are explained by shot noise generation at the RTD. Theoretical results suggest that reducing the valley current as well as reducing the series resistance would realize RTT noise performance superior to HJFETs