Influence of acceptor-type trap states on 2DEG density in β-(Al0.15Ga0.85)2O3/Ga2O3 HFET

This work investigates the impact of acceptor-type traps in interface and channel region on the two-dimensional electron gas (2DEG) density in β-(Al 0.15 Ga 0.85 ) 2 O 3 /Ga 2 O 3 heterostructure field-effect transistors (HFETs) using an improved physics-based 2DEG model. Deep-level transient spectroscopy (DLTS) is employed to extract the density of states (DoS) associated with acceptor-type traps located at the β-(Al 0.15 Ga 0.85 ) 2 O 3 /insulator interface region and within the β-(Al 0.15 Ga 0.85 ) 2 O 3 /Ga 2 O 3 channel region. These traps are classified into deep-level and band-tail states, each exerting distinct impacts on 2DEG density. Numerical simulations reveal that acceptor-type in channel region exert a stronger effect on 2DEG density than those at the interface, with deep-level states particularly reducing the effective gate voltage due to their significant carrier trapping under electrostatic influence. The findings underscore the critical importance of minimizing trap densities—particularly in the channel region—to enhance 2DEG density and optimize β-(Al x Ga 1-x ) 2 O 3 /Ga 2 O 3 HFET performance.