Based On The People’s Armed Police Force Network Office Automation System Research And Implementation

PDP (Plasma Display Panel) is a mainstream of flat panel display in the market. Ithas good display effect， long lifetime， high look-angle， high response speed， etc.But the design of high voltage power devices in the scan driver of plasma display panelis very important and difficult.The purpose of the paper is to design a set of high voltage devices includePLDMOS (P-channel Lateral Double-diffused MOSFET) and NLDMOS (N-channelLateral Double-diffused MOSFET) in the voltage level shift circuits and LIGBT(Lateral Insulated Gate Bipolar Transistor) in the output stage. They were based on thicklayer SOI (Silicon On Insulator) and will be used in scan driver of plasma display panel.The thickness of Si is12μm and the thickness of the buried layer is1μm. Compared toconventional Si process， SOI has many merits， such as higher speed， lower powerdissipation， high integration， easy to isolation， less parasitic effects， etc. Thedevices based on thick layer SOI has bigger current density and lower self-heatingcompare to devices based on thin layer SOI. We has replaced the LDMOS in the outputstage by LIGBT， which has good current ability can improve the speed of the scan IC.The function and the principle of the PDP scan driver IC has been introducedfirstly. Then introduced the isolation theory in the PDP scan driver IC， Shallow TrenchIsolation has been used between the low voltage units， also between the drain andsource of the high voltage devices. On the other hand，double Deep Trench Isolation hasbeen used between the high voltage units， also between the high voltage units and thelow voltage units. The Trench Isolation can reduce the isolation area greatly， avoid theparasitic effects and improve the integration and reliability of scan driver ICremarkable.Two dimensional simulation softwar medici has use to investigate the off-statecharacteristic， threshold voltage and the on-state characteristics of PLDMOS，NLDMOS and LIGBT. The parameter of the devices such as the length and dopeconcertration of the drift region， the length of field plate， the doping concentration ofchannel，the location of the trench groove has been optimized for good performance. In order to reduce the latch-up effect in LIGBT a deep P+region near the emitter regionhas been induced. Besides， Field Stop LIGBT gives a good tradeoff between forwardon-state voltage and turn off energy. At last， the self-heating of SOI LIGBT has beendiscussed. After the simulation， all the devices gain big forward biased safe operatingareas and the breakdown voltages of the are more than175V. The saturations current ofthe LIGBT exceed2×10-4A/μm， and its turn off times only10-6s. All of the highvoltages devices designe in this papers are qualified for PDP scan driver IC.