| 摘要 |
PURPOSE:To prevent decrease in threshold voltage and in breakdown strength between a source and a drain and to suppress leak currents to the side of a substrate by providing impurity-doped region whose impurity concentration is higher than the impurity concentration of the semiconductor substrate and which has the same conductivity type as that of the substrate directly beneath a gate electrode at a specified depth, and setting the position of the peak of the impurity concentration within a specified distance from the surface of the substrate. CONSTITUTION:An n-type impurity layer 10' and a p-type impurity layer 10 are provided in an n-type protruding region 13' and a p-type protruding region 12' directly beneath gate electrodes 16 of p-type and n-type transistors. The impurity concentrations of the layers 10' and 10 are higher than that in the regions 13' and 12'. The position of the peak of the impurity concentration is set within approximately 0.8mum from the surface of the substrate. Since the two-dimensional distribution of depletion layers in the regions 12' and 13' can be suppressed, the decrease in threshold voltage can be suppressed. Since the electric field of a drain is weakened by the layers 10' and 10, punch-through between a source and the drain is suppressed, and breakdown strength between the source and the drain is improved. |
