Method for making a DRAM cell with grooved transfer device
First Claim
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1. A method of fabricating a semiconductor device comprising the steps of:
- forming in a substrate a groove having a sub-lithograplic width;
forming a grooved gate in said groove, said grooved gate having sidewall portions and a bottom portion, and defining a channel located in said substrate along said gate sidewall and bottom portions, wherein sidewall sections of said channel located along said gate sidewall portions have a larger length than a bottom length of a bottom section of said channel located along said gate bottom portion; and
forming first and second regions in said substrate on opposite sides of said grooved gate, respectively.
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Abstract
A memory cell having a grooved gate formed in a sub-lithographic groove, and methods of making thereof are disclosed. The groove extends the channel length to include the groove sidewalls and width of the groove. Sidewall sections of the channel located along the gate sidewalls have a larger length than the bottom channel section length located along the gate bottom width. Thus, the memory device is primarily controlled by the sidewall channel sections, instead of the bottom channel section. The groove may be a stepped groove formed by a two step etch to further increase the channel length and may be formed centered along the gate conductor width.
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Citations
35 Claims
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1. A method of fabricating a semiconductor device comprising the steps of:
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forming in a substrate a groove having a sub-lithograplic width; forming a grooved gate in said groove, said grooved gate having sidewall portions and a bottom portion, and defining a channel located in said substrate along said gate sidewall and bottom portions, wherein sidewall sections of said channel located along said gate sidewall portions have a larger length than a bottom length of a bottom section of said channel located along said gate bottom portion; and forming first and second regions in said substrate on opposite sides of said grooved gate, respectively. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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35. A method of manufacturing a memory cell comprising the steps of:
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forming a deep trench capacitor in a substrate doped with a first type of impurity, said deep trench capacitor having a plate electrode formed in said substrate and a storage electrode; forming first and second regions doped with a second type of impurity in said substrate, said first region being connected to said storage node of said deep trench capacitor; forming a groove in said substrate between said first and second regions; and forming a grooved gate in said groove and beyond said groove extending a lateral distance over said substrate to control a resistance of a channel located in said substrate between said first and second regions;
said groove gate extending a length of said channel to include sidewalls of said groove, a width of said groove, and said lateral distance.
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Specification