Study On High-Voltage Structure Of Large-Power LDMOS

As one of the popular research directions in high-voltage and high-power devices,Lateral Double-diffused Metal-Oxide-Semiconductor(LDMOS)needs to possess both high performance and high reliability.Among them,Silicon-On-Insulator(SOI)high-voltage devices,known for their excellent isolation performance and low power consumption,have become a major focus in LDMOS research.However,during the research process,SOI devices themselves have some issues such as self-heating effects,which limit their further development.Partial Silicon-On-Insulator(PSOI),as an effective means to mitigate self-heating effects,has gained widespread attention in recent years.Considering the excellent characteristics and broad prospect of SOI structure,this paper proposes four new device structures on the basis of traditional SOI devices,and uses Sentaurus TCAD for simulation,analyzes their principle,device voltage resistance mechanism and a series of simulation results,so as to improve device performance.At first,In this paper,based on the basic overview of LDMOS and SOI LDMOS as the starting point,respectively introduced the research status,working principle and other content,described the RESURF,and described the advantages and disadvantages of SOI device,research mechanism,as well as the improved structure of field plate,low k dielectric buried layer,charge trench,trench and superjunction.Secondly,two new structures of SOI are proposed,namely one with a single triangular buried oxygen layer and one with multiple triangular buried oxygen layers.On the basis of traditional SOI devices,a triangular layer is added above the buried oxygen layer in the former,and multiple identical triangular layers are added in the latter.The triangular buried oxygen layer can not only participate in the surface electric field of the modulator parts,so that the electric field of the device in the transverse is evenly distributed,increasing the breakdown voltage,but also introduce higher density charge at the interface of the buried oxygen layer to enhance the electric field of the buried oxygen layer,and thus improve quality factor of the device.Thirdly,based on the high performance of PSOI,two new structures of PSOI are proposed,PSOI LDMOS with a single triangular buried oxygen layer and PSOI high voltage device structure with multiple triangular buried oxygen layers.On the basis of traditional SOI devices,a silicon window is added,and a triangular oxygen layer is added above the buried oxygen layer,and the latter is added with multiple identical triangular oxygen layers.The PSOI can make the substrate of the device participate in voltage resistance,alleviate the self-heating effect of the device,further improve the breakdown voltage of the device,reduce the on-resistance,improve quality factor of the device.and provide a new direction for the development of SOI devices.Finally,a summary of the above work is provided,along with plans and prospects for future research phases.