SOI high voltage device used for the PDP line scan driver IC
|School||University of Electronic Science and Technology|
|Course||Microelectronics and Solid State Electronics|
|Keywords||PDP scan driver ICs thick layer SOI NLDMOS PLDMOS LIGBT|
The development of the digital signal transmission requires higher-performance display receivers. As one of the new flat panel display devices the plasma display panel (PDP) has attracted a lot of attention for its merits such as high response speed, large screen and high-resolution. As for PDP the driver ICs plays a major part in the whole cost. The PDP driver ICs includes low-voltage logic and mixed signal part and high-voltage part. With the feature size reducing, logic and mixed signal part takes a decreasing chip area. However, the high voltage part, especially the power device, demands a nearly constant area. This makes the power devices dominate in the whole chip area. Therefore, It is meaningful to improve the high-voltage part of the driver to reduce the whole cost. The high-volatge of the The PDP driver ICs includes level shift circuit and output.The main work of the paper is to design SOI high voltage power devices for the use of PDP scan driver ICs, Including the NLDMOS and PLDMOS in the level shift circuit and NLIGBT in the output. We use deep trench isolation (DTI) among high voltage cells and between high voltage cell and low voltage cell, dielectric isolation reduces the isolation area to improve the integration of PDP scan drive ICs, compared with the PN junction isolation the chip area reduced by 70 percent. For the PDPs have been developed toward large screens and high resolution, the equivalent capacitance to be driven increases proportionally, for this reason we use LIGBTs to replace the traditional LDMOSs as output to increase the drive current of the PDP scan driver ICs.In this paper we first study the basic theory of the breakdown characteristic, including the off-state and on-state. Two-dimensional simulation software Medici has been used to analyze the relationship between the electrical parameters and the structure parameters of the device. The structure parameters of the devices includes such as doping concentration of the drift and channel region,the length of field plate,etc. Finally the device structure parameters are optimized to meet the demand of the static electrical parameters. When designing the process of the PDP scan drive IC, we first use device structure parameters to choose appropriate process, the TCAD software Tsuprem4 and Medici are used to modify the process parameters to fit the electrical characteristics of the devices. Finally, finish the layout design of the PDP scan drive ICs. The first tape out is completed, the breakdown voltages of devices are more than 200V , the saturation current density of the LIGBT exceeds 4×10-4A/μm and its turn off time only 10-7s, the results meet the electrical characteristics demand of the PDP scan driver IC.