Method for the formation of buried gates of a semiconductor device utilizing etch and refill techniques
AssigneeToyo Denki Seizo Kabushiki Kaisha
InventorKimihiro Muraoka
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Abstract
A method for the formation of buried gates in a semiconductor device using epitaxial growing method combined with diffusion method or diffusion by an additional heat treatment. The buried gate has smaller gate resistance by providing relatively high impurity concentration and also having good reverse characteristic by providing relatively low impurity concentration at the top of the buried gates.
Claims7
A method of forming buried gates in a semiconductor silicon substrate, said method comprising the steps of:
- providing a reentrant shaped groove in said silicon substrate;
- diffusing into said groove a layer having a medium surface impurity concentration;
- epitaxially growing a first layer on said diffusion layer, said first epitaxially grown layer having a higher impurity concentration than said diffusion layer;
- epitaxially growing a second layer on said first epitaxially grown layer, said second layer having a lower impurity concentration than said diffusion layer;
- and
- providing a single crystal silicon layer over said substrate and said second epitaxially grown layer, said single crystal silicon layer having a conductivity similar to said semiconductor silicon substrate.
A method of forming buried gates in a semiconductor silicon substrate, said method comprising the steps of:
- providing a reentrant shaped groove in said silicon substrate;
- diffusing into said groove a layer having a high surface impurity concentration;
- epitaxially growing a first layer on said diffusion layer, said first epitaxially grown layer having a lower impurity concentration than said diffusion layer;
- epitaxially growing a second layer on said first epitaxially grown layer, said second layer having a lower impurity concentration than said first epitaxially grown layer;
- and
- providing a single crystal silicon layer over said substrate and said second epitaxially grown layer, said single crystal silicon layer having a conductivity similar to said semiconductor silicon substrate.
A method of forming buried gates in a semiconductor silicon substrate, said method comprising the steps of:
- providing a reentrant shaped groove in said silicon substrate;
- diffusing into said groove a layer having a high surface impurity concentration;
- epitaxially growing a first layer on said diffusion layer, said first epitaxially grown layer having a high impurity concentration;
- epitaxially growing a second layer on said first epitaxially grown layer, said second layer having a lower impurity concentration than said diffusion layer;
- and
- providing a single crystal silicon layer over said substrate and said second epitaxially grown layer, said single crystal silicon layer having a conductivity similar to said semiconductor silicon substrate.
A method of forming buried gates in a semiconductor silicon substrate, said method comprising the steps of:
- providing a reentrant shaped groove in said silicon substrate;
- diffusing into said groove a layer of semiconductor material having a surface impurity concentration;
- epitaxially growing a first layer on said diffusion layer, said first epitaxially grown layer having a surface impurity concentration;
- epitaxially growing a second layer on said first epitaxially grown layer, said second epitaxially grown layer having a surface impurity concentration less than either of said diffusion layer or said first epitaxially grown layer;
- and
- providing a single crystal silicon layer over said substrate and said second epitaxially grown layer, said single crystal silicon layer having a conductivity similar to said semiconductor silicon substrate.
Dependencies are inferred from the claim text.