NDE Of Power MOSFET's Resisting Radiation Ability

Power MOS devices, especially the VDMOS devices, which are compatible with the VLSI process and developing fast, are becoming the main force of power devices. Meantime, Power MOS devices are used widely in the field of irradiation, e.g. navigation, spaceflight, nuclear power station, military electronics. To make sure the reliability of work and depress the cost, a reliable and low cost NDE (Nondestructive evaluation) method is badly needed to evaluate the endurance of power MOS device which is going to be used in irradiation environment.This paper studied on the effects and damages of irradiated power MOS devices, and the mechanism of 1/f noise; then, ionization irradiation experiment was done; based on this, NDE model and method of power MOS device's endurance in irradiation environment was studied; farther research was done about the DC-DC converter's NDE; at last, DC-DC converter's lift prognostic cell was designed.After all the works done,1,The experiment showed, after the irradiation, power MOS devices'threshold floats to the negative direction; Transconductance falls; leakage current rises; extent of 1/f noise rises. Meantime, the swing of NMOS ten times high than PMOS, so the PMOS is more fit for the radiation use.2,Degenerate of power MOS device can influence the DC-DC converter badly: Threshold's negative float makes the efficiency of DC-DC converter falls; leakage current and turn on resistance's rise makes the power cost of DC-DC rise; rise of 1/f noise's extent makes the whole DC-DC's 1/f noise rise.3,Built up the NDE model for power MOS device anti-radiation ability, which concerns the relationships of: 1/f noise and radiation dose; border traps and 1/f noise; threshold floats and 1/f noise.4,Built up the NDE method for power MOS device anti-radiation ability.5,Built up the NDE method for DC-DC converter anti-radiation ability.6,Based on the power MOS switch radiation failure, designed the prognostic cell for DC-DC converter life.