Method of boron doping wafers using a vertical oven system

Abstract

The present invention relates to a method for boron doping wafers using a vertical oven system. The vertical oven system (1) used comprises a vertical reaction chamber (2) that extends from an upper end toward a lower end and comprises several independently heated temperature zones (5a-5e). An upper temperature zone (5a) is provided on a gas intake (6) for a boron-containing reactive gas. The additional zones (5b-5e) follow the upper end in the direction toward the lower end of the reaction chamber (2). With this method, the boron-containing reactive gas flows over the wafers (4) inside the reaction chamber. The boron from the boron layer, deposited in this way on the wafers, subsequently diffuses into the wafer surface. The method according to the invention provides that the temperature of the additional zones (5b-5e) is adjusted such that it is possible to maintain a temperature increase during the deposit across the additional zones and a temperature drop toward the lower end of the reaction chamber (2) during the diffusion across the additional zones. A high uniformity of the produced doping profile can thus be achieved across the individual wafers as well as across the reaction chamber. The same is true for the reproducibility of the doping profile between individual process cycles.

Dependencies are inferred from the claim text.