The temperature coefficient of the threshold voltage in long buried-p-channel MOSFET is

mV/°C, which is much larger than that in the long enhancement-mode n-channel MOSFET (-1.27 mV/°C). The difference is caused by the charge freeze-out phenomenon in the buried-channel MOSFET. The absolute value of the temperature coefficient of the threshold voltage

, decreases with decreasing channel length in the n-channel MOSFET, however, it increases with decreasing channel length in the submicrometer p-channel MOSFET. The difference results from the majority-carrier spill-over phenomenon in the buried-p-channel MOSFET.