| 摘要 |
PURPOSE:To reduce the capacitance of a diffusion layer and realize high speed operation by providing a low impurity concentration diffused layer which has the same conductivity type as the drain region directly under and apart from the drain region. CONSTITUTION:A gate oxide film 15 and a polycrystalline Si gate electrode 14 are formed on an N-type Si substrate 11 with insulating isolation layers 12 by RIE with a resist mask 13. Then B ions 16 are implanted with the acceleration voltage of 200keV and successively BF2 ions 18 are implanted with the voltage of 40keV to form a P<->type layer 17 and a P<+>type layer 19 and a heat treatment is performed to form a P<+>type source region 20 and a P<+>type drain region 21 and P<->type layers 20a and 21a are formed directly under and apart from those regions 20 and 21. Then an SiO2 film 22 is applied and an aperture 23 is formed and Al wiring 24 is attached. With this constitution, the width of a depletion layer between the drain region 21 and the substrate 11 can be extended compared to the conventional constitution and the capacitance is reduced so that the high speed operation of the device can be realized. |
