| Intelligent power driver IC is a power chip with a driver circuit, power devices, sensors and various protection circuits, especially for all types of motor and inverter power supply. Lateral insulated gate bipolar transistor as a core device in intelligent power driver chip, shoulder the transmission function of low voltage to high voltage and low power to high power. As a switch device, it needs to have fast switching characteristics. Improve the turn-off rate of the device while maintaining the rest of electrical parameters without degradation is a current research focus.In this thesis, based on the technology platform of thick insulating substrate of silicon, the thesis do some deep research about the turn-off process of LIGBT, and a detailed analysis of the turn-off mechanism at inductive load conditions, including the carrier distribution during the former turn-off period, the movement path of of carriers, the carrier distribution and recombination process during the tailing period, and so on. Based on this study, the thesis studied several existing LIGBT device structure with characteristic of fast turn-off effect, and analyzed their advantages and disadvantages respectively.The thesis proposed a new thick-film SOI-LIGBT device, which increased the segmented trench isolation structure for guiding the carrier, the N+collector structure for quick extraction of electron, and the P+ collector structure for improving hole injection efficiency. And this new LIGBT device can improve the turn-off speed without degradation of any other electrical parameters. Then the new proposed LIGBT structure has been optimized by the way of simulation, and was taped for test.The final test results show that the proposed thick-film SOI-LIGBT device has fast turn-off characteristics while maintaining the rest of electrical parameters without degradation. And the turn-off time reduced from 572ns to 189ns, improved about 66.96%. |
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