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APPLICATIONS OF ION IMPLANTATION TO THE CONTROL OF DYNAMIC CHARACTERISTICS IN POWER DEVICES
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| Author(s) |
F. Frisina; N. Tavolo; G. Ferla; S. U. Campisano; S. Coffa |
| Abstract |
Ion implantation and diffusion of platinum and gold has been used to reduce to optimum values the minority carrier lifetime in power MOS and in insulated gate bipolar transistors (IGBT) without appreciable worsening of their static characteristics. Ion implantation of metallic impurities offers the unique advantage of a precise control of the total amount of trap centers and the possibility to get impurity profiles that cannot be obtained by conventional deposition and diffusion methods. In order to fully characterize the process we have investigated the diffusion mechanism and the compensating effects of implanted metals. We have applied the method to the fabrication of high voltage power MOS devices in order to increase the switching speed of the internal diodes thus optimizing the unavoidable increase of the on- resistance. As an example, for platinum implantation at a dose of 10to13 / cm² we get a 10% increase in Ron and a 90% reduction of the reverse recovery charge. These values, that can be varied by changing the Pt fluence, are compared with those obtained by gold implantation or deposition. Platinum implantation has been also adopted in the fabrication of IGBT; it has been measured an increase of the latch-up current density (to values larger than 600 A / cm² at 100°c) and a fall time of less than 200ns. The trade off between static and dynamic characteristics (V-cesat vs t-fall) is compared with figures obtained by other methods of lifetime reduction. |
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| Filesize: | 3.73 MB |
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| Type |
Members Only |
| Date |
Last modified 2019-06-10 by System |
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