【作者】 刘倩；

【导师】 孙伟锋； 苏巍；

【作者基本信息】 东南大学 ， 集成电路工程（专业学位）， 2021， 硕士

【摘要】 分裂栅功率金属氧化物半导体场效应晶体管（Metal-Oxide-Semiconductor Field-Effect Transistor,MOSFET）具有开关速度快、损耗小等优点,广泛应用于通信、工业自动化、交通运输及消费电子等领域。热插拔技术能够在不中断系统工作的条件下对系统进行维护,从而提高系统的可靠性。热插拔技术要求功率MOSFET器件在高压大电流条件下工作更长时间（毫秒级）,即具有更宽的安全工作区（Safe Operating Area,SOA）。然而,分裂栅功率MOSFET器件为了获得更低的特征导通电阻,不断减小芯片面积,导致其SOA大大缩小,无法满足热插拔技术的要求。本文旨在对传统分裂栅MOSFET器件的SOA进行优化,设计具有宽SOA的分裂栅功率MOSFET器件。本文首先对分裂栅功率MOSFET器件的工作原理进行介绍,详细阐述了器件的电学特性与安全工作区。然后对器件超出安全工作区的失效机理进行分析,发现二次击穿是导致器件失效的主要原因,而二次击穿主要与温度系数有关。随后,分析了P型体区掺杂浓度等参数对温度系数的影响。在此研究基础上,首先提出了断沟道分裂栅具有宽SOA的器件结构。断沟道结构通过减小器件沟道宽度实现宽SOA的效果,但是该结构会增加器件的导通电阻。为此,在断沟道的基础上提出了一种新型复合栅结构,该结构通过引入平面栅,可在不增加导通电阻的前提下实现更宽的SOA。因此复合栅功率MOSFET器件具有最优结构。仿真结果显示,设计的复合栅功率MOSFET器件击穿电压为108V,阈值电压为4.2V,特征导通电阻为4.85mΩ/cm²,SOA二次击穿限为38A/cm²(V_ds=56V,time=10ms),各项性能参数均达到设计指标要求。更多还原

【Abstract】 Split gate power MOSFET devices are widely used in communication,industrial automation,transportation and consumer electronics for the advantages of high switching speed,low loss.The system can be maintained without interruption by hot swap technology,so as to improve the reliability of the system.Split gate power MOSFET devices with wider safe operating area(SOA)are required in hot swap technology.However,in order to obtain lower characteristic on resistance,the chip area is becoming smaller and smaller,resulting in the SOA greatly reduced,which can not meet the requirements of hot swap technology.The purpose of this research is to optimize the SOA of traditional split gate MOSFET and design a split gate power MOSFET with wide SOA.Firstly,the working principle of split gate power MOSFET is introduced,and the electrical characteristics and safe working area of the device are described in detail.Then the failure mechanism of the device operating beyond the safe working area is analyzed.It is found that the secondary breakdown is the main cause of the device failure,and it is mainly related to the temperature coefficient.Then,the effects of pbody doping concentration on the temperature coefficient are analyzed.Based on the study,a device structure with wide SOA are proposed,which is split gate with open channel.The open channel structure achieves wide SOA by reducing the channel width,however,increasing the on resistance of the device.Therefore,based on the open channel,a new type of composite gate structure is proposed,which can realize a wider SOA without increasing the on resistance by introducing planar gate.So the composite gate power MOSFET is the optimal structure.The simulation results show that the breakdown voltage of the composite gate power MOSFET device is 108 V,the threshold voltage is 4.2V,the on-resistance is 4.85mΩ,the SOA boundary is38A/cm~2.So all performance parameters are up to design index requirements.更多还原