Analysis of microwave noise in an enhancement-mode dual-quantum-well InAs HEMT

Abstract

A systematic theoretical study is carried out on the microwave noise performance of an InAs-based dual-quantum-well double-gate high-electron mobility transistor. The proposed dual-quantum-well HEMT shows prominent small-signal analog/radiofrequency (RF) and noise performance. The results for a device with a gate length of 30 nm reveal enhancement-mode operation with a threshold voltage (Vt) of 0.146 V and high transconductance of 4.77 S/mm along with a cutoff frequency (ft) of 810 GHz and maximum oscillation frequency (fmax) of 900 GHz for Vds = 0.5 V with reduced parasitic capacitance (Cgg) of 0.003 pF/mm. The high-frequency noise of this device is estimated from the gate and drain noise spectral densities evaluated by a Green’s function method under varying bias conditions. This device shows a minimum noise figure (NFmin) of 1.62 dB in combination with an equivalent noise resistance of 972 Ω at 810 GHz for Vgs = 0.6 V and Vds = 0.5 V, which is relatively low and suitable for the design of low-noise amplifiers for use in high-frequency applications. This study shows that such an InAs HEMT with a dual-quantum-well structure is highly suitable for use in higher-frequency applications that require low noise.