A new expression for breakdown voltage of practical linearly graded p-n junction

An analytical investigation of realistic linearly graded silicon p-n junctions, currently used in high-voltage device structures, is performed. Basic corrections to the fundamental theory of reverse-biased, linearly graded p-n junctions are analytically formulated. Closed-form relations for the breakdown voltage BV and peak space-charge region extension (at breakdown) in practical linearly graded junctions are presented. A thorough investigation of linearly graded junctions used in power devices is performed. Basic corrections to the fundamental theory of linearly graded junctions have been analytically formulated. It is shown that the departure from the classical linearly graded case is more obvious as the background impurity concentration drops below C/sub B/=10/sup 15/ cm/sup -3/ and the impurity gradient a increases above 5*10/sup 16/ cm/sup -4/. For C/sub B/10/sup 16/ cm/sup -4/, the linearly graded junction behaves like an abrupt one. For a>10/sup 19/ cm/sup -4/ and C/sub B/<10/sup 16/ cm/sup -3/, the linearly graded case is reduced to the abrupt one.