| 摘要 |
PROBLEM TO BE SOLVED: To provide the polycrystalline silicon resistance element of high performance and high resistance, which has the less fluctuation of a resistance value by Al wiring thermal treatment. SOLUTION: The polycrystalline silicon film 12 of about 150 nm is formed on a field oxidized film 11 formed on a silicon substrate 10 by a CVD method. N-type impurity (phosphorus, for example) and P-type impurity (boron, for example) are ion-implanted into the polycrystalline silicon film 12 so that total concentration in polycrystalline silicon becomes not less than 1×1020 cm-3. Phosphorus is ion-implanted so that impurity concentration becomes 1.7×1020 cm-3 and boron is ion-implanted so that impurity concentration becomes 2×1020 cm-3. The total concentration of N-type impurity and P-type impurity, which are thus implanted, becomes 3.7×1020 cm-3 but they are mutually canceled. Thus, only 3×1019 cm-3 of P-type impurity contributes to conduction and high resistance whose specific resistance is about 1×10-1Ω.cm can be realized.
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