Nitride semiconductor device

摘要

A nitride semiconductor device is provide that can reduce contact resistance of an ohmic electrode and a nitride semiconductor layer. In a GaN HFET, recesses (106, 109) are formed in a nitride semiconductor multilayer body (20) composed of an undoped GaN layer (1) and an undoped AlGaN layer (2) formed on an Si substrate (10), and a source electrode (11) and a drain electrode (12) are formed in the recesses (106, 109). In a region deeper than an interface (S1, S2) between the GaN layer (1) and the source electrode (11) and drain electrode (12), which are formed from a TiAl material, a first chlorine concentration peak (P11) is formed in vicinity of the interface, and a second chlorine concentration peak (P22) having a chlorine concentration of 1.3×1017 cm−3 or lower is formed at a position deeper than the first chlorine concentration peak (P11).

主权项

1. A nitride semiconductor device comprising:
a substrate; a nitride semiconductor multilayer body formed on the substrate and having a heterointerface; and ohmic electrodes which are made from a TiAl material and at least part of which are formed on the nitride semiconductor multilayer body or in the nitride semiconductor multilayer body, wherein the nitride semiconductor multilayer body includes: a first nitride semiconductor layer formed on the substrate; and a second nitride semiconductor layer formed on the first nitride semiconductor layer to make up a heterointerface in combination with the first nitride semiconductor layer, and wherein a chlorine concentration distribution in a depthwise direction over a range from the ohmic electrodes formed from the TiAl material to the nitride semiconductor multilayer body has: a first chloride concentration peak at a position in vicinity of an interface between the ohmic electrodes and the nitride semiconductor multilayer body and in a substrate side region from the interface; and a second chlorine concentration peak at a position deeper than the first chloride concentration peak, and wherein the chlorine concentration of the second chlorine concentration peak is within a range of 3×1016 cm−3 to 1.3×1017 cm−3.