Semiconductor devices by the use of new interfacial reactions and interfacial compounds.

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We have developed the following new semiconductor processes in order to improve the electrical characteristics of metal-oxide-semiconductor (MOS) diodes : 1) elimination of interface states at Si/SiO_2 interfaces by "cyanide treatment", 2) low temperature formation of Si/SiO_2 structure by the use of chemical methods, and 3) low tempertaure formation of Si/silicon oxynitride structure by the use of the low energy impact plasma method. In the case of 1), it has been found that interface states are eliminated by the selective reaction of cyanide ions with Si dangling bonds by the immersion of the Si/SiO_2 structure in KCN solutions. Si-CN bonds resulted from the cyanide treatment possess a high bond energy of 4.5 eV, leading to the thermal stability at 800℃ and the irradiation stability. It is found that contamination by K^+ ions can be completely prevented by the inclusion of crown-ether (C_<12>H_<24>O_6) in the KCN solutions. The leakage current is markedly decreased by the cyanide tre … More atment. In the case of 2), it is found that SiO_2 layers can be formed at 〜300 ℃ by the use of the catalytic activity of a platinum (Pt) layer. When the Pt treatment which involves the deposition of a Pt layer followed by the heat treatment at 〜300 ℃ in oxygen is performed on 〜2 nm SiO_2/Si structure, the density of the leakage current is decreased to 〜1/200. O^- ions produced by the catalytic activity of Pt are injected to SiO_2, leading to the passivation of defects and the formation of uniform SiO_2 layers. Methods of the fabrication of Si and SiC-based MOS diodes at 〜200 ℃ are developed by the use of perchloric acid. The fabricated MOS diodes possess low interface state densities even without hydrogen treatment. In the case of 3), a method of the formation of silicon oxynitride layers at 25〜450 ℃ is developed by the use of nitrogen plasma generated by the low energy impact method. Plasma damages introduced in the silicon oxynitride layers are found to be eliminated by the use of method 2) (i.e. Pt treatment). Less