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|United States Patent||6,794,709|
|Ahn ,   et al.||September 21, 2004|
Structures and methods involving at least a pair of gate oxides having different thicknesses, one suitable for use in a logic device and one suitable for use in a memory device, have been shown. The method provided by the present invention affords a technique for ultra thin dual gate oxides having different thicknesses using a low temperature process in which no etching steps are required. The method includes forming a pair of gate oxides to a first thickness, which in one embodiment, includes a thickness of less than 5 nanometers. In one embodiment, forming the pair of gate oxides includes using a low-temperature oxidation method. A thin dielectric layer is then formed on one of the pair of gate oxides which is to remain as a thin gate oxide region for a transistor for use in a logic device. The thin dielectric layer exhibits a high resistance to oxidation at high temperatures. In one embodiment, the thin dielectric layer includes a thin dielectric layer of silicon nitride (Si.sub.3 N.sub.4) formed using jet vapor deposition (JVD). The other of the pair of gate oxides is then formed to a second thickness to serve as a thick gate oxide region for a transistor for use in a memory device. Another embodiment of the present invention includes the structure of a logic device and a memory device formed on a single substrate as well as systems formed according to the method described above. In one embodiment, a dielectric layer of the transistor for use in the logic device has a thickness of less than 7 nanometers and a dielectric layer in the transistor for use in the memory device has a thickness of less than 12 nanometers.
|Inventors:||Ahn; Kie Y. (Chappaqua, NY); Forbes; Leonard (Corvallis, OR)|
|Assignee:||Micron Technology, Inc. (Boise, ID)|
|Filed:||August 30, 2001|
|Current U.S. Class:||257/315; 257/52; 257/298|
|Intern'l Class:||H01L 029/788|
|Field of Search:||257/36,52,298,315,344,347,239,275,279,296,327,329,317 438/239,279,294,298,315,327|
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|6124171||Sep., 2000||Arghavani et al.||438/286.|
|6222788||Apr., 2001||Forbes et al.||365/230.|
|6358819||Mar., 2002||Shelton et al.||438/433.|
|6597046||Jul., 2003||Chau et al.||257/411.|
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