US 2019/0103462 A1Published application

Silicon carbide semiconductor device

AssigneeFuji Electric Co., Ltd.

InventorShinichiro MATSUNAGA

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Abstract

For example, a pin diode is constituted by a silicon carbide epitaxial substrate in which silicon carbide epitaxial layers constituting an n-type buffer region, an n−-type drift region, and a p++-type anode region are sequentially formed by epitaxial growth on a front surface of an n+-type silicon carbide substrate. The n−-type drift region has an n-type impurity concentration is, for example, about 1×1014/cm3 to 1×1016/cm3. The n−-type drift region has a boron concentration that is substantially lower than an n-type impurity concentration of the n−-type drift region and that, for example, is about 1×1014/cm3 or less. During epitaxial growth of the n−-type drift region, automatic doping of boron to the n−-type drift region is suppressed, whereby the boron concentration of the n−-type drift region is reduced and the n−-type drift region in which no traps are present is formed.

Claims4

Dependent claims

A silicon carbide semiconductor device comprising:

a semiconductor substrate of a first conductivity type and containing silicon carbide;
a first semiconductor region provided on a surface of the semiconductor substrate and constituted by a silicon carbide crystal layer of the first conductivity type and having an impurity concentration lower than an impurity concentration of the semiconductor substrate;
and
a second semiconductor region of a second conductivity type provided on a first side of the first semiconductor region, opposite a second side of the first semiconductor region facing toward the semiconductor substrate, the second semiconductor region forming a pn junction with the first semiconductor region, wherein
an impurity concentration of a first impurity of the first conductivity type of the first semiconductor region is at most 1×1016/cm3, and
an impurity concentration of boron that is a second impurity different from the first impurity of the first conductivity type of the first semiconductor region is lower than the impurity concentration of the first impurity of the first conductivity type of the first semiconductor region and is at most 1×1014/cm3.

3 more elements

Dependencies are inferred from the claim text.