| 摘要 |
PURPOSE:To obtain an Mo gate MOS transistor having little fluctuations in threshold voltage when a +bias temperature (BT) test is performed by a method wherein the molybdenum film, which will be used as a gate electrode, is formed while the temperature of a substrate is being maintained within the range of prescribed temperature. CONSTITUTION:A field oxide film and a gate oxide film are formed on a silicon substrate, an Mo films having 1,000Angstrom , 3,000Angstrom and 6,000Angstrom in thickness are formed. An Mo gate electrode formed by performing an etching, an As ion is implanted for the purpose of forming a source and drain layer, and a silicon oxide film is formed as an interlayer film. After a contact hole has been provided, an Al film having Si is formed, and the transistor is formed by performing a patterning. The result of measurement of the dependency of stress application period of threshold voltage fluctuation in a +BT test is shown in the diagram. Almost no Mo film thickness dependency is observed. The appropriate lowest limit of substrate temperature when the Mo film is formed is 700 deg.C, and 1,100 deg.C is considered to be the appropriate uppermost limit of same. |
