Two methods have been developed for the preparation of large‐areap‐njunctions in monocrystalline silicon by surface melting and overdoping of the molten material. In one method, direct rf power coupling is used to form a cylindricalp‐njunction in a rod of silicon. Also, radiation heating has been used to melt the surface of thin disks of silicon. The junctions can sustain a peak inverse voltage (PIV) given approximately by PIV=40&rgr;nor PIV=10&rgr;pdepending on the polarity of the base material, of resistivity &rgr;nor &rgr;p. Low‐resistivityn‐type base material overdoped with aluminium forms junctions exhibiting very sharp breakdown characteristics, and PIV=40&rgr;nholds for material at least up to 15 ohm cm. Some results obtained by using a gas doping technique are also given.