| 摘要 |
PURPOSE:To prevent a sheet resistance of a conductive semiconductor from becoming highly resistive and to maintain the uniformity of the sheet resistance by a method wherein a thin thermal oxide film is formed on the conductive semiconductor deposited after an impurity has been contained and, after that, a heat treatment to activate the impurity is executed. CONSTITUTION:First-Iayer polysilicon 3 which has been doped with phosphorus is deposited on an insulating film 2 formed on a subStrate 1; an oxide film of a capacitance insulating film 4 is formed; after that, a heat treatment to activate the phosphorus is executed; in addition, second-layer polysilicon 5 is deposited; a capacitance is formed of polysilicon 3, 5 by two layers and of the capacitance insulating film 4. When the thin thermal oxide film 4 is formed on the conductive semiconductor polysilicon 3 deposited after an impurity has been contained and the heat treatment to activate the impurity is executed in this manner, a sheet resistance of the polysilicon 3 deposited after it has been doped with phosphorus can be kept low and sufficiently uniform even under a condition that its surface is thermally oxidized. |
