This paper describes the results of a two-dimensional numerical analysis of a normally-off-type buried-channel MOSFET (BC MOSFET). This device has two operation modes whose boundary is a flat-band voltage. Bulk current is a main current when

. Short-channel effects, like the decrease of a threshold voltage, were examined. Devices with a thinner gate oxide, a shallower channel depth, and a higher substrate concentration are effective for the short-channel effect.