Semiconductor device and method of fabricating the same
According to the embodiments, a semiconductor device using SiC and having a high breakdown voltage, a low on-resistance, and excellent reliability is provided. The semiconductor device includes a silicon carbide substrate having first and second main surfaces; a first silicon carbide layer of a first conductive type provided on the first main surface of the silicon carbide substrate; first silicon carbide regions of a second conductive type formed on a surface of the first silicon carbide layer; second silicon carbide regions of the first conductive type formed on respective surfaces of the first silicon carbide regions; third silicon carbide regions of the second conductive type formed on the respective surfaces of the first silicon carbide regions; a fourth silicon carbide region of the second conductive type formed between the facing first silicon carbide regions with the first silicon carbide layer therebetween; a gate insulating film formed continuously on surfaces of the first silicon carbide regions, the first silicon carbide layer, and the fourth silicon carbide region; a gate electrode formed on the gate insulating film; an interlayer insulating film which covers the gate electrode; a first electrode which is electrically connected to the second silicon carbide regions and the third silicon carbide regions; and a second electrode formed on the second main surface of the silicon carbide substrate.
1. A semiconductor device comprising:
a silicon carbide substrate having first and second main surfaces;
a first silicon carbide layer of a first conductive type provided on the first main surface of the silicon carbide substrate, the first silicon carbide layer having impurity concentration of 5×10 15 to 2×10 16 cm −3 ;
first silicon carbide regions of a second conductive type formed at a surface of the first silicon carbide layer, the first silicon carbide regions having impurity concentration of 1×10 17 to 5×10 17 cm −3 ;
second silicon carbide regions of the first conductive type formed at respective surfaces of the first silicon carbide regions;
third silicon carbide regions of the second conductive type formed at the respective surfaces of the first silicon carbide regions;
a fourth silicon carbide region of the second conductive type formed between the facing first silicon carbide regions with the first silicon carbide layer therebetween, the fourth silicon carbide region having impurity concentration of 1×10 17 to 5×10 18 cm −3 ;
a gate insulating film formed continuously on surfaces of the first silicon carbide regions, the first silicon carbide layer, and the fourth silicon carbide region;
a gate electrode formed on the gate insulating film;
an interlayer insulating film configured to cover the gate electrode;
a first electrode being configured to electrically connect to the second silicon carbide regions and the third silicon carbide regions; and
a second electrode formed on the second main surface of the silicon carbide substrate,
wherein a distance between the facing first silicon carbide regions is 1.0 μm to 4.0 μm.
2. The device according to claim 1 , wherein a depth of the fourth silicon carbide region is shallower than a depth of the first silicon carbide regions.
3. The device according to claim 1 , wherein an impurity of the second conductive type contained in the fourth silicon carbide region is aluminum.
4. The device according to claim 1 , wherein the silicon carbide substrate is of the first conductive type and configures a MOSFET.
5. The device according to claim 1 , wherein the silicon carbide substrate is of the second conductive type and configures an IGBT.