Trench Schottky Barrier Controlled Schottky Rectifiers
As discussed in the previous chapter, the leakage current for silicon and silicon carbide Schottky rectifiers can be greatly reduced at high reverse bias voltages by shielding the metal contact from the high electric field generated within the semiconductor. The approach utilized in the previous chapter is based up on creating P-N junctions located under the Schottky contact with carefully chosen spacing between them to create a potential barrier under the metal contact during the reverse blocking mode. One of the short-comings of this approach is the need to anneal the ion implanted P-type regions at very high temperatures in order to activate the dopant and remove the lattice damage. At these high temperatures, some dissociation can occur at the semiconductor surface which degrades the quality of the metal-semiconductor junction that must be subsequently formed. Although an issue for silicon devices, this problem is particularly severe for silicon carbide due to the very high (∼1600 oC) annealing temperature for activation of ion implanted regions.
KeywordsBarrier Height Leakage Current Schottky Barrier Breakdown Voltage High Electric Field
- 1.L. Tu and B.J. Baliga, “Schottky Barrier Rectifier including Schottky Barrier Regions of Differing Barrier Heights”, U. S. Patent 5,262,668, Issued November 16, 1993.Google Scholar
- 2.M. Praveen, S. Mahalingam, and B.J. Baliga, “Silicon Carbide Dual Metal Schottky Rectifiers”, PSRC Technical Working Group Meeting Report, TW-97-002-C, 1997.Google Scholar
- 3.B.J. Baliga, “Silicon Carbide Power Devices”, World Scientific Publishing Company, 2005.Google Scholar
- 5.B.J. Baliga, “Modern Power Devices”, Chapter 4, John Wiley and Sons, 1987.Google Scholar
- 6.B.J. Baliga, “High Voltage Silicon Carbide Devices”, Material Research Society Symposium, Vol. 512, pp. 77–88, 1998.Google Scholar