Influence of Effective Fixed Charges on Short-Channel Effects in SiC Metal-Oxide-Semiconductor Field-Effect Transistors

Influence of effective fixed charges, which are located near the metal-oxide-semiconductor (MOS) interface, on short-channel effects in 4H-SiC MOS field-effect transistors (FETs) has been investigated. The relationship between the threshold voltage and the channel length was theoretically calculated by using an original charge-share model, which takes the effective fixed charges into account. As a result, it was revealed that the effective fixed charges, which are attributed to electron trapping at the interface states, affect the relationship. The threshold voltage is decreased by reducing the channel length in the relatively-long channel region when the effective fixed charges exist. The theoretical relationship between the threshold voltage and the channel length calculated by using the proposed model agrees very well with the experimental results. (C) 2010 The Japan Society of Applied Physics