An interesting N-shaped negative differential resistance (NDR) switch based on AlInAs/GaInAs high electron mobility transistor is fabricated and demonstrated. Under forward gate voltage, the presence of two terminal negative differential resistance can be attributed that the electrons sequentially tunneling from GaInAs channel into gate region through triangular barrier, delta-doped AlInAs layer, and triangular Schottky barrier. An extremely broad gate voltage swing larger than 5 V is obtained. Furthermore, the extremely large gate-to-drain breakdown voltage is achieved. For the studied device, the unit current cutoff frequency f(T) and maximum oscillation frequency are up to 32 and 48 GHz, respectively. Consequently, due to the presented NDR and the excellent transistor performance, the studied device provides a good potential for linear and analog amplification, high frequency, and logic circuit applications. (C) 2003 Elsevier Ltd. All rights reserved.