| 摘要 |
The invention relates to a method of manufacturing a high-voltage element, in particular, but not exclusively, an LDMOS transistor in SOI with a drift region (13) which has a linearly increasing doping concentration between a back-gate region (8) and a drain (6). A doping mask (15) is used for doping the drift region, in which mask the pitch between the windows becomes smaller in the direction from source to drain at least within part of the drift region. This is achieved in an embodiment by means of windows which have identical dimensions but which lie closer together in proportion as they lie closer to the drain. It was found in experiments that a smooth doping profile can be obtained in this manner, so that peaks in the doping, and thus in the electric field, are avoided. The degree of impact ionization is reduced thereby, which benefits the robustness of the transistor. |
