| Summary: | 碩士 === 東海大學 === 電機工程學系 === 102 === When lateral insulated gate bipolar transistor (LIGBT) turns on, there is a hole current injecting from the P+-anode heading to underneath and lateral area. The hole current flowing to p-type substrate will cause substrate leakage current and influence the electric circuit around. According to the method of avoiding substrate leakage current, using p-type buried layer (PBL) and n-type buried layer (NBL) to form pn-junction can increase horizontal electric field and decrease vertical electric field, therefore, the hole will not injecting to the substrate. However, due to process limitation, the depth and doping concentration of the p-type buried layer are not easy to control. Although using p-type buried layer can avoid substrate leakage current, it also decreases the turn on current. This research work aims at fabricating LIGBT with p-type epitaxial layer to replace the PBL, along with the original NBL and n-epi drift region. Therefore, the double epitaxial layer technology is adopted. TCAD tools of Medici and Tsuprem4 are used to simulate device properties and process conditions. The results show that the device’s breakdown voltage can maintain over 700 volts, meanwhile, it can avoid the hole substrate current and has lower turn on resistance.
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