Electrical characteristics of Hf-based GaAs MOS capacitors with thin HfOxNy interlayer

Electrical and reliability characteristic of Hf-based GaAs metal-oxide-semiconductor (MOS) capacitors (TaN/HfO₂/HfO_xN_y/p-GaAs) with ultrathin HfO_xN_y interfacial layer is investigated. Charge trapping behavior has been studied under both the DC and dynamic voltage stressing. Transient response and the degradation mechanism of the dielectric have been studied both under positive and negative DC gate bias stressing conditions. Effect of interfacial layer thickness variation on flat band voltage instability is reported. It is found that both the interface and bulk traps in gate stacks contribute significantly to flat band voltage instability of HfO₂-based GaAs MOS capacitors. Both types of trapping are observed under dynamic stressing with the gate hole injections.