Trenched semiconductor device and method of fabricating the same
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorKATSUMI NAKAMURA
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Abstract
In a trenched MOS gate power device having a trenched MOS gate structure, a gate insulating film is formed on the walls of trenches to extend onto a major surface of a semiconductor substrate, and gates are formed so as to fill up the trenches and to extend onto the gate insulating film on the major surface of the semiconductor substrate. The gate insulating film is formed so that the thickness of a portion thereof formed on the major surface of the semiconductor substrate is greater than that of a portion thereof formed on the walls of the trenches to narrow portions of the gates corresponding to the tops of the trenches. Thus, the characteristics of a gate insulating film formed on the walls of trenches are improved.
Claims14
A trenched semiconductor device comprising:
- a semiconductor substrate provided with at least one trench in a major surface thereof;
- an insulating film formed on the wall of the trench and extending onto the major surface of the semiconductor substrate;
- and
- a conductive part filling up the trench and extending on to the insulating film on the major surface of the semiconductor substrate.
A trenched semiconductor device comprising:
- a semiconductor substrate provided with at least one trench in a major surface thereof;
- and
- an insulating film formed on the wall of the trenches and extending onto the major surface of the semiconductor substrate;
- and
- a conductive part formed at least in the trench;
- wherein the thickness of the portion of the insulating film on the major surface of the semiconductor substrate is at least twice of the thickness of the portion of the insulating film on the wall of the trench.
Dependencies are inferred from the claim text.