Method of manufacturing a semiconductor device

In a method of producing a semiconductor arrangement including applying a diffusion masking layer to one surface of a semiconductor body, forming a first semiconductor region of a first type of conductivity by opening a first diffusion window in said masking layer and diffusing said first semiconductor region into the semiconductor body via said window, forming a second semiconductor region of a second type of conductivity completely within said first semiconductor region so that the p-n junction between said first and second semiconductor regions extends to a portion of the semiconductor surface which is covered by said diffusion masking layer prior to and during said step of diffusing said first semiconductor region of the first type of conductivity, the improvement wherein said step of forming a second semiconductor region of the second type of conductivity comprises opening a second diffusion window in said masking layer which is greater than said first diffusion window for producing said semiconductor region of the first type of conductivity, and diffusing said second semiconductor region of the second type of conductivity into said first semiconductor region via said second diffusion window so that said second semiconductor region of the second type of conductivity is substantially thinner than said first semiconductor region of the first type of conductivity.