| 摘要 |
A storage cell comprising an MOS field-effect transistor having a high storage capacitance provided by one of its two p-n junctions, is produced in the surface of a semiconductor crystal by at least three diffusion or implantation steps. In a preliminary masked doping step at a surface area E of crystal (1), a region (7) is produced of the same conductivity type as the crystal (1) but more strongly doped. Within region (7), the one zone (2) of the field-effect transistor forming the storage capacitance is produced in two redoping steps. In the first step, employing a mask exposing an area A of the semiconductor surface there is produced a region (2) of the opposite conductivity type to that of crystal (1) defining a p-n junction lying within region (7). In the second step, employing a mask exposing only a sub-area B of area A, a dopant producing the same conductivity type as that of region (7) is introduced until the remaining part of redoped region (2) acquires the L-shaped profile shown. <IMAGE> |
