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SOI LDMOS device is a new type of power semiconductor devices based on LDMOS devices. SOI structure has a high-speed, low-power, high-integration, anti-radiation, easy isolation advantages, and can overcome the shortcomings of the bulk silicon material, is widely used in high-voltage integrated circuits and power integrated circuits. The high-voltage integrated circuits in weapons and equipment, power electronics, industrial automation, aerospace and other high-tech industries has a broad application prospects. Many domestic and foreign researchers have proposed a variety of device structures improved SOI LDMOS devices, mainly focused on two aspects of the device breakdown voltage and on-resistance, thereby improving the performance of the device. The main content of this article is a SOI LDMOS breakdown voltage and specific on-resistance. Mainly includes two device structures: of SOI LDMOS (FG SOI LDMOS) having a floating gate structure and the trench structure SOI LDMOS (T SOI LDMOS). Specific contents are as follows: (1) having a floating gate structure SOI LDMOS device, the device structure is characterized by the distribution of a plurality of polysilicon gate on the field oxide layer in the device, the repeated use of the class field plate junction termination technique, the adjusting device of the transverse electric field distribution, improve the device breakdown voltage, lower than the guide on-resistance. Silvaco TCAD through simulation software simulation results showed that the number in the same size of the device under conditions optimized to give, by the number and size of the floating gate when the floating gate 5, a length of 0.5 μm, the floating gate structure SOI LDMOS device breakdown voltage increased by 38.9%, 20.5% lower than the on-resistance. Finally, the self-heating effect of the device was analyzed. (2) SOI LDMOS device having a trench structure, the structural characteristics of the device is below the edge of the gate, the surface of the drift region of the device etched trench structure, and the material of the trench is silica, since the The material critical breakdown field than the critical breakdown field of the silicon to be high and it can withstand a higher electric field strength. The presence of the trench structure, to improve the breakdown voltage of the device in the case of not raise the conduction resistance of the device, so that the performance of the device is improved. Silvaco's TCAD by simulation software, a simulation result of the device structure that SOI LDMOS device compared with the conventional structure, in the same device structure of dimensions under conditions, by the size of the trench be optimized, and obtained when the length of the trench 6μm, the thickness of the trench for the 1.5μm, trench structures SOI LDMOS device breakdown voltage increased 26.7%, 14.3% lower than the on-resistance. Finally, the analysis of the thermal effect of the device's self, the device can be mitigated to a certain extent self-heating effects.
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