| 摘要 |
PURPOSE:To realize a resistor of a desired high resistance value without affecting transistor characteristics by a method wherein an oxide film formed on an impurity layer is locally removed for the formation of an opening and the semiconductor substrate is subjected to thermal oxidation for the formation of an oxidized impurity layer on top of the impurity layer just under the opening. CONSTITUTION:On a semiconductor substrate 1 of one conductivity type, an insulating film 3 equipped with a first opening is formed. Through the first opening, an impurity opposite to the substrate 1 in conductivity is diffused into the semiconductor substrate 1 for the formation of an impurity layer 5. Next, an oxide film formed on the impurity layer 5 is locally removed for the formation of a second opening 6, which is followed by a process wherein the semiconductor substrate 1 is subjected to thermal oxidation for the formation of a oxidized impurity layer 3 on top of the impurity layer 5 just under the second opening 6. For example, a lowresistance P-type impurity layer 5 is formed on an N-type silicon substrate 1 and a second opening 6 is provided in an silicon oxide film on top of a region to develop into a high-resistance layer. After this, wet thermal oxidation is accomplished for the conversion of the low-resistance layer upper portion into a silicon oxide layer 3. Such a low-resistance layer is thin enough to allow the formation of a high-resistance layer 5.
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