Research And Optimization Of High Voltage SOI Device With Multiple Trench In The Drift Region

The intelligent power module is an integrated circuit module which composes of a driving circuit and power devices.It is efficient and intelligent.The single chip intelligent power module integrates all the components of the intelligent power module on the same chip to realize the miniaturization and high reliability of the system.For a typical intelligent power module,the power device acts as a core component,occupying most of the area of the module.The development trend of intelligent power module requires that the power devices have higher current density and lower switching losses.The trench structure is introduced into the drift region of the power device.It is the current research dircction that optimize the current capability and turn-off performance of the device while maintaining the rest of electrical parameters without degradation.Firstly,this thesis elaborates the current status of the trench structure in the drift region at home and abroad,and analyzes the effect of the drift region on the voltage resistance mechanism,forward conduction characteristics and switching characteristics of thick film SOI devices.Secondly,the electrical characteristics of the deep oxidation trench(DOT)device in the drift region are analyzed,and the potential distribution,carrier distribution and current distribution of the device under different conditions are analyzed by simulation.Thirdly,the improved structure of several existing DOT structures is studied,and the advantages and disadvantages of these structures are analyzed.Based on this,this thesis proposes a multiple deep oxide trench(MDOT)device.The device with stepped multiple trench structure will enhance the current capability of the device,and improve the turn-off performance of the minority device,while maintaining the breakdown voltage.Finally,this thesis designed the process and layout for the MDOT devices.The test results show that the current density of the proposed MDOT lateral insulated gate bipolar transistor(LIGBT)increased from 246A/cm2 to 354A/cm2,and the turn-off time reduced from 330ns to 146ns.The on-resistance of the proposed MDOT lateral double diffused MOSFET(LDMOS)reduced from 0.414k?·cm2 to 0.104k?·cm2.The reverse-recovery time of the proposed MDOT fast recovery diode(FRD)reduced from 280ns to 124ns.These devices meet the design requirements.