The Dmos Anti-radiation Study Of The Key Technologies And The New Structure Of The Device

As a basic power device, the power switch VDMOS is always used for power integrated circuits and power integrated system with its high breakdown voltage and high conductivity characteristics. VDMOS is greatly used in nuclear radiation and space radiation environments, so the research of the VDMOS radiation hardened technologies is very important. A novel partial SOI VDMOS (PSOI VDMOS) device structure is proposed in paper. The partial SOI is introduced to the VDMOS device, so the novel structure device keeps the excellent power characteristics and improved the breakdown voltage, frequency and radiation harden characteristics.First, the principal work of this thesis is to clarify the foundational effect of partial SOI VDMOS, The forward conduction characteristics and the reverse blocking characteristic of this device are analyzed in details. The 2-D potential model and on-resistance model of partial SOI VDMOS is obtained. The partial buried oxide change the distribution of potential and electric field, take much less effect on epi- resistance, which is the main part of low voltage VDMOS, it significantly improve the blocking voltage behavior of the device without reducing its on-resistance.Second, the characteristics of this novel PSOI VDMOSFET device are numerically analyzed. The three-dimensional device simulator ISE and two-dimensional device simulator Medici are applied to simulate the radiation effect on the device. It shows that with the same device parameter, the transient radiation toleration of PSOI VDMOS is at less 2 times than that of the conventional VDMOS. The critical LET threshold of PSOI VDMOS is two times than that of the conventional VDMOS. It is shown that the anti-radiation ability of the PSOI VDMOS is more and better.Based on the successful radiation harden project of my team, the layout and process of PSOI VDMOS is been studied, and so is the POWER device radiation testing system.