JPS6437867A - Semiconductor device - Google Patents

Abstract

PURPOSE:To bring an alignment margin to zero, and to enable the improvement of the degree of integration by conducting a kind of self-alignment-like ion implantation using a gate electrode. CONSTITUTION:Gate electrodes 103 through a gate oxide film 102 and gate electrodes 107 through a gate oxide film 105 are arranged alternately on an silicon substrate 101, and impurity layers 104 for controlling threshold voltage are formed near the surface of Si only in sections, threshold voltage of which must be fluctuated, in the electrodes 103. There is no ion implanting layer at sections where thresholds are not changed, and there are ion implanting layers at sections where thresholds do not exceed the thresholds of the electrodes 107 among the electrodes 103. There are impurity layers 106 for controlling threshold voltage only at sections, thresholds of which must be altered, under the electrodes 107. Accordingly, the ion implanting impurity layers for controlling threshold voltage are shaped in a self-alignment manner with the gate electrodes.