A semiconductor device having a buried gate electrode and method for its preparation

A semiconductor device having a transistor (216, 218) with a buried gate electrode (126), said semiconductor device comprising: a semiconductor body (102) surrounded by a grave one isolation region (108) active area (104, 106); a recess (118) in a surface of the active region (104, 106) and in the grave isolation region (108); a recess (118) lining the dielectric layer (120); and a recess (118) only filling an electrode material, wherein a dopant region (124) is formed in the active region at the bottom of the recess (118) containing the channel region and the source / drain regions (228) are formed such that they abut the channel region adjacent a side wall of the recess (124); and wherein the dopant region has its highest dopant concentration of the recess (118).