The present invention relates to methods of producing semiconductor PN junction devices, and more specifically relates to PN junction types of rectifier devices, tunnel rectifier devices, photoelectric conversion devices and capacitor devices.
In the fabrication of a conventional PN junction device a surface portion of a semiconductor layer of one conductivity type is doped with an impurity of the opposite conductivity type by means of ion implantation or conventional diffusion technology.
However, impurity doping by ion implantation has certain drawbacks, including: the semiconductor layer surface is damaged due to kinetic energy of the doping impurity; a shallow diffusion layer cannot be easily formed due to the occurrence of channeling; and a steep impurity concentration profile cannot be created in a deep portion because the doped impurity is distributed in the form of a Gaussian distribution having a variance determined by the acceleration energy.
In turn, the conventional diffusion technology has drawbacks such as, for example, that the diffusion density and junction depth cannot be accurately controlled because the impurity doping is carried out generally through an oxide film barrier over the semiconductor layer surface.