PMOS TRANSISTORS, INTRINSIC-MOBILITY AND THEIR SURFACE DEGRADATION PARAMETERS AT CRYOGENIC TEMPERATURES

The intrinsic low-field mobility μo and the mobility surface-degradation constants θo and θB in varying channel length pMOS transistors at cryogenic temperatures are presented. It was found that μo increased from 180 cm2/V s at 300 K to 1260 cm2/V s at 77 K, and that θo also increased with 0.10 at 300 K to 0.49 at 77 K. These two parameters were extracted using an analytical model for the pMOS devices in its ohmic mode of operation that is very suitable for use in circuit simulation programs such as SPICE.