Physical and Electrical Properties of rf Plasma Grown Al₂O₃ and ain Insulators on Silicon

Abstract

RF plasma-enhanced chemical-vapour deposition(PECVD) is fast emerging as a powerful technique for depositing insulating films at low temperatures (⁢ 500°C) for semiconductor device applications. In this paper, the physical and electrical properties of AI₂O₃ and AIN films grown in a laboratory-built RF PECVD system are discussed. The Al- Al₂O₃-SiO₂ -Si (MAOS) capacitors show electron injection and trapping into Al₂O₃ film under negative gate-bias above a threshold voltage. The charge trapping has been found to be strongly dependent on the post deposition annealing treatment of Al₂O₃ films, The I—V characteristics have been derived from capacitance voltage (C—V) measurement in presence of charge injection. The trapped charge in the Al₂O₃ is stable and cannot be detrapped by applying positive gate voltage. An MAOS transistor has been fabricated and its characteristics compared with a standard MOS transistor.

The AIN films have been grown in the temperature range of 400–600°C. Like Al₂O₃, uniform, smooth adherent films of AIN have been obtained on silicon. Reflection electron diffraction (RED) experiments show that the films are amorphous. The films have been used for passivation applications. Some of the electrical properties of the AI-AIN- SiO₂ Si (MA_NOS) capacitors have been described. The effect of post-deposition annealing treatment on the electrical properties of AIN films has been investigated.

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Notes on contributors

A.B. Bhattacharya

PROF. BHATTACHARYA, A B (Dr.): (b. 1937). Received MSc. degree in Physics in 1958 and PhD (communication) in 1961 from Banaras Hindu University. Subsequently he served as a lecturer in the same university till 1967 in the Electrical Engg. Department. He was appointed as Assistant Professor in the Physics Department and Professor in the Electrical Engineering Department in the year 1967 and 1973 respectively at IIT, Delhi.

He is responsible for organising and co-ordinating the microelectronics laboratory at IIT, Delhi. His interests are in the area of micro-electronics technology, silicon devices, surface acoustic waves and MOS-based devices.

Sudhir Chandra

SUDHIR CHANDRA (b. 1950, Bareilly). Obtained BSc and MSc (Physics) degrees from Agra University at Bareilly College, Bareilly, in 1968 and 1970 respectively, and MTech in solidstate physics from IIT, Delhi in 1972. At present, he is working as senior scientific officer in the Centre for Applied Research in Electronics, IIT, Delhi. His research interests include semiconductor-insulator interfaces, dielectric films and MOS devices.

D. Nagchoudhuri

NAGCHOUDHURI, D (Dr) (b. 1944 Agra). After obtaining his BTech in Electronics from IIT, Kharagpur, he worked at various places including TIFR Bombay and CDIL, Faridabad. Later, he obtained MS and PhD degrees from Michigan State University, USA. Since 1974, he has been on the faculty in IIT Delhi. His R & D interests are largely in the area of micro electronics, especially in MIS structures and MOS-based devices. He is also associated with the development of micro-electronics laboratory facility at IIT Delhi.