Charge pumping source-drain current for gate oxide interface trap density in MOSFETs and LDMOS

In this paper, we obtained interface trap density through source-drain CP (charge pumping) current, instead of conventional substrate CP current in MOSFETs and LDMOS. We observed that interface density is same for both source drain CP current and substrate CP current when LOCOS (local oxidation of Silicon) field oxide is used to separate substrate (body) and source in different channel MOSFETs. However, source-drain CP current is higher than substrate CP current when modern STI (shallow trench isolation) is used to separate the substrate and source in different channel MOSFETs. The difference between I_ds and I_sub is independent on I_base voltage. Furthermore, we showed that the source-drain CP current is a useful method for interface traps in LDMOS. We observed that interface traps density is higher in drift region than in channel region in LDMOS.