A New Doping Technique Without SiO2 Patterning Using an Inorganic Photoresist

A new impurity doping technique, using patterned inorganic photoresist as the diffusion source, is proposed. The inorganic resist films employed are (Se‐Ge)‐based ternary systems with donor or acceptor impurity as the third component. Diffusion process steps are described in detail. Both n‐ and p‐type doping into Si are successfully achieved with this technique. The fabricated p + ‐n and n + ‐p diodes exhibit good p‐n characteristics and are not at all inferior to those fabricated by the conventional method. A double diffused n‐p‐n transistor was also fabricated utilizing this technology. The incorporation of Se or Ge into Si is shown to be essentially negligible, as a result of SIMS analysis. This doping technique does not require the formation and patterning of an oxide mask. Process simplification and several other advantages can be expected.