| 摘要 |
PURPOSE:To obtain withstanding voltage in the same extent as conventional devices even when the film thickness of an epitaxial layer is thinned by forming a first conductivity type impurity layer shaped by reversely doping an impurity having concentration lower than a first conductivity type semiconductor sub strate and a second conductivity type reverse to a first conductivity type into the semiconductor substrate. CONSTITUTION:A first conductivity type impurity layer 21 shaped by doping an impurity having concentration lower than a first conductivity type high- concentration semiconductor substrate 20 and a second conductivity type reverse to a first conductivity type is formed into the semiconductor substrate 20. Accordingly, a drift layer is thickened equivalently, thus realizing an element having a withstand-voltage much higher than those of conventional devices while the film thickness of epitaxial layer being the same. Even when the film thickness of the epitaxial layer is made thinner, on the contrary, a withstand- voltage in the same extent as conventional devices is acquired, thus lowering the cost of an IC. |
