Silicon carbide semiconductor device having nitrogen-containing silicon alloy for ohmic contact to P-type impurity region

摘要

A semiconductor device includes: a first silicon carbide semiconductor layer; a p-type first impurity region provided in the first silicon carbide semiconductor layer; and a first ohmic electrode forming ohmic contact with the p-type first impurity region. The first ohmic electrode is a silicon alloy containing nitrogen, an average concentration of nitrogen in the first ohmic electrode is higher than or equal to one half of an average concentration of nitrogen in the first impurity region, and an average concentration of a p-type impurity in a portion of the first ohmic electrode except a portion of the first ohmic electrode within 50 nm from an interface between the first ohmic electrode and the first impurity region is equal to or lower than 3.0×1018 cm−3.

主权项

1. A semiconductor device comprising:
a first silicon carbide semiconductor layer; a first impurity region having a p-type conductivity throughout, and provided in the first silicon carbide semiconductor layer; and a first ohmic electrode forming ohmic contact with the first impurity region, wherein the first ohmic electrode is a silicon alloy containing nitrogen, an average concentration of nitrogen of the first ohmic electrode above an area where the first impurity region is in direct contact with the first ohmic electrode is higher than or equal to one half of an average concentration of nitrogen in the first impurity region, and is higher than or equal to 6.9×1018 cm−3, and an average concentration of a p-type impurity in a portion of the first ohmic electrode except a portion of the first ohmic electrode within 50 nm from an interface between the first ohmic electrode and the first impurity region is equal to or lower than 3.0×1018 cm−3.