Sputter deposition of thin films for high mobility poly-Si TFT fabrication

This article describes the sputter deposition - using a glow discharge plasma - of thin films for low-temperature fabrication of high mobility poly-Si TFTs. Silicon film, gate SiO2 film and interlevel SiO2 film are sputter deposited. Poly-Si films with grain sizes of several tens to hundreds of nanometers are formed by the sputtered amorphous Si film followed by argon laser irradiation at room temperature. The gate and interlevel SiO2 films are sputter deposited from an SiO2 target in oxygen- and hydrogen- argon mixtures, respectively. The resulting poly-Si TFTs show very high mobilities of 383 cm2/V .s despite the small grain sizes of the poly-Si films. The electrical characteristics of the poly-Si TFTs are analyzed and the TFTs are successfully applied to integrated circuits. (orig.)