Method of fabricating semiconductor device with MIS structure
First Claim
1. A method of fabricating a semiconductor device, comprising the steps of:
- (a) forming a silicon nitride film on a semiconductor substrate;
(b) ion-implanting oxygen into said silicon nitride film and by heat-treating said oxygen-implanted silicon nitride film, thereby forming an oxygen-doped silicon nitride film having an oxygen-rich region that extends along an interface between said oxygen-doped silicon nitride film and said substrate;
said oxygen-rich region being higher in oxygen concentration than a remainder of said oxygen-doped silicon nitride film;
at least part of said oxygen-doped silicon nitride film serving as a gate insulator film of a MISFET;
(c) forming a gate electrode of said MISFET on said oxygen-doped silicon nitride film;
(d) selectively introducing a dopant into said substrate to form a pair of source/drain regions of said MISFET in said substrate at each side of said gate electrode; and
(e) heat-treating said substrate to activate said dopant introduced into said substrate in said step (d).
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Abstract
A fabrication method of a semiconductor device with the MIS structure is provided, which prevents the boron penetration phenomenon from occurring even if a gate insulator film is as thin as approximately 3 nm or less. After a silicon nitride film is formed on a semiconductor substrate, oxygen is doped into the silicon nitride film by a suitable process such as a thermal oxidation, ion implantation or plasma doping process, thereby forming an oxygen-doped silicon nitride film having an oxygen-rich region that extends along an interface between the oxygen-doped silicon nitride film and the substrate. The oxygen-rich region is higher in oxygen concentration than the remainder of the oxygen-doped silicon nitride film. At least part of the oxygen-doped silicon nitride film serves as a gate insulator film of a MISFET. Next, a gate electrode of the MISFET is formed on the oxygen-doped silicon nitride film. A dopant is selectively introduced into the substrate to form a pair of source/drain regions of the MISFET in the substrate at each side of the boron-doped gate electrode. Finally, the substrate is heat-treated to activate or anneal the dopant introduced into the substrate.
42 Citations
16 Claims
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1. A method of fabricating a semiconductor device, comprising the steps of:
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(a) forming a silicon nitride film on a semiconductor substrate; (b) ion-implanting oxygen into said silicon nitride film and by heat-treating said oxygen-implanted silicon nitride film, thereby forming an oxygen-doped silicon nitride film having an oxygen-rich region that extends along an interface between said oxygen-doped silicon nitride film and said substrate; said oxygen-rich region being higher in oxygen concentration than a remainder of said oxygen-doped silicon nitride film; at least part of said oxygen-doped silicon nitride film serving as a gate insulator film of a MISFET; (c) forming a gate electrode of said MISFET on said oxygen-doped silicon nitride film; (d) selectively introducing a dopant into said substrate to form a pair of source/drain regions of said MISFET in said substrate at each side of said gate electrode; and (e) heat-treating said substrate to activate said dopant introduced into said substrate in said step (d). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of fabricating a semiconductor device, comprising the steps of:
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(a) forming a silicon nitride film on a semiconductor substrate; (b) plasma-doping oxygen into said silicon nitride film and heat-treating said oxygen-implanted silicon nitride film, thereby forming an oxygen-doped silicon nitride film having an oxygen-rich region that extends along an interface between said oxygen-doped silicon nitride film and said substrate; said oxygen-rich region being higher in oxygen concentration than a remainder of said oxygen-doped silicon nitride film; wherein at least part of said oxygen-doped silicon nitride film serves as a gate insulator film of a MISFET; (c) forming a gate electrode of said MISFET on said oxygen-doped silicon nitride film; (d) selectively introducing a dopant into said substrate to form a pair of source/drain regions of said MISFET in said substrate at each side of said gate electrode; and (e) heat-treating said substrate to activate said dopant introduced into said substrate in said step (d). - View Dependent Claims (11, 12, 13, 14, 15, 16)
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Specification