High-voltage silicon Trench Sidewall OXide-Merged p-i-n/Schottky (TSOX-MPS) rectifier

The principles underlying the operation of a novel silicon Trench Sidewall OXide Merged p-i-n/Schottky (TSOX-MPS) rectifier have been studied. The effect of different design parameters, such as trench width, mesa width, Schottky barrier height, and carrier lifetime on the performance of the rectifier have been explored in detail. A process has been developed and implemented for the fabrication of a 400V TSOX-MPS rectifier by integrating the necessary planar device processing and trench etch processing.;The TSOX-MPS rectifier switches several times faster than a conventional p-i-n rectifier with the same static characteristics. Further, for the same switching performance, the TSOX-MPS rectifier has a lower forward drop and lower reverse leakage when compared to the p-i-n rectifier. The reverse leakage current for the TSOX-MPS rectifier is over two orders of magnitude lower than the leakage current reported for a conventional planar MPS rectifier.;A two-dimensional model was developed to simulate the forward conduction characteristics of the TSOX-MPS rectifier. The coupled behavior of the p+-n junction and the Schottky contact in forward conduction is explained. A reverse current model was developed by using Poisson's equation and incorporating Schottky barrier lowering effects. The models developed compares reasonably well with the experimentally measured forward and reverse I--V characteristics.;While the present TSOX-MPS rectifier research has emphasized 400 V operation, the structure is suitable for higher voltage rectifiers as well. Numerical and analytical modeling indicates the potential of realizing 1200V and 3000V rectifiers with appropriately designed device structures.