Insight into low frequency noise induced by gate leakage current in AlGaAs/GaAs high electron mobility transistors at 4.2 K

The bias-cooling method—the gate being kept biased at V_gc during the cooling—has been used to investigate the low frequency noise (LFN) in an AlGaAs/GaAs two-dimensional electron gas high electron mobility transistor at 4.2 K. For a chosen working point (i.e., a chosen drain bias/current), its gate bias V_gs, gate leakage current I_gs, and LFN depend on V_gc. With the help of the heterostructure band diagram simulation for each V_gc, the relation between I_gs and the LFN can be elucidated by the gate Fermi level with regard to the heterostructure band diagram. The LFN originated from I_gs is caused by its sequential tunnelling component.