Method of making semiconductor devices having two-layer gate structure
AssigneeMicron Technology, Inc.
InventorsViju K. Mathews, Charles H. Dennison, Pierre Fazan, Roy Maddox, Akram Ditali
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Abstract
The present invention includes a method of forming semiconductor oxide layers and, in particular, gate oxide layers, in MOS semiconductor devices formed on silicon substrates. The method includes the steps of forming a first silicon oxide sublayer on the silicon substrate in an atmosphere including primarily oxygen, and forming a second silicon oxide sublayer over the first sublayer in an atmosphere including primarily nitrous oxide (N.sub.2 O). Preferably, the first and second sublayers represent 80 percent and 20 percent, respectively, of the silicon oxide layer.
Claims19
A method of forming a gate oxide layer on a semiconductor substrate for a MOS semiconductor device, comprising the steps:
- forming a first gate oxide sublayer on the semiconductor substrate in a first atmosphere including primarily oxygen;
- and
- forming a second gate oxide sublayer having a thickness of about 0.95 nm to 3 nm, the second gate oxide sublayer being formed on the first oxide sublayer in a second atmosphere including primarily nitrous oxide.
A method of forming a composite gate oxide layer on a <100>-oriented lightly doped p-type substrate for a MOS semiconductor device, comprising:
- providing a first reaction atmosphere containing substantially oxygen;
- heating the substrate from about a room temp to a first reaction temperature;
- forming on the substrate a first gate oxide sublayer having a thickness of about 9 nm to 11 nm;
- heating the substrate from the first reaction temperature to a second reaction temperature;
- providing a second reaction atmosphere containing substantially nitrous oxide;
- and
- forming on the first gate oxide sublayer a second gate oxide sublayer having a thickness of about 0.95 nm to 3 nm.
A method of forming a gate oxide layer of a selected thickness on a semiconductor substrate for a MOS semiconductor device, comprising the steps:
- forming a first gate oxide sublayer on the semiconductor substrate in a first atmosphere including primarily oxygen;
- and
- forming a second gate oxide sublayer on the first oxide sublayer in a second atmosphere including primarily nitrous oxide, the first gate oxide sublayer having a thickness of between about 75 and 92 percent the selected thickness of the gate oxide layer and the second gate oxide sublayer having a corresponding thickness of between about 25 percent and 8 percent of the selected thickness.
Dependencies are inferred from the claim text.