High deposition rate a-Si:H for the flat panel display industry
- Tokyo Electron America, Beverly, MA (United States)
- Utrecht Univ. (Netherlands)
- Princeton Univ., NJ (United States). Dept. of Electrical Engineering
High deposition rates and good quality electrical properties and thickness uniformities over large areas are required for all three films (SiN{sub x}, a-Si:H and n{sup +} a-Si:H) composing the thin film transistors (TFTs) for the AMLCD industry, while maintaining high tool up-time and low particle formation. Generally these conditions have been achieved for most single-panel multichamber PECVD systems; however, it has become increasingly apparent that a compromise is drawn between the TFT mobility and the deposition rate of the a-Si:H layer. Thus it becomes essential to clearly assess the industry requirements for both deposition rates as well as TFT performance for the different device structures used for AMLCDs, and to discover and control these underlying material properties. The TEL VHF (40/60 MHz) PECVD system produces high quality, low defect density a-Si:H at deposition rates exceeding 1,500 {angstrom}/min when analyzed by FTIR, CPM, photo and dark conductivity. Even though the low deposition rate a-Si:H exhibits very similar bulk properties, higher mobility TFTs are produced with a-Si:H deposited at lower RF power. Having both a high ion flux and low ion energy in the SiH{sub 4} discharge are likely the most critical conditions for controlling the a-Si:H quality and thus the TFT mobility. Increasing the RF frequency enhances both of these effects, as well as provides a higher deposition rate for a given power density and a higher power threshold for particle/powder formation. For these reasons it is likely a 40/60 MHz plasma will produce better performing TFTs for a given deposition rate when compared with a conventional 13.56 MHz system.
- OSTI ID:
- 527619
- Report Number(s):
- CONF-960401-; ISBN 1-55899-323-1; TRN: IM9741%%47
- Resource Relation:
- Conference: Spring meeting of the Materials Research Society (MRS), San Francisco, CA (United States), 8-12 Apr 1996; Other Information: PBD: 1996; Related Information: Is Part Of Amorphous silicon technology -- 1996; Hack, M. [ed.] [dpiX, Palo Alto, CA (United States)]; Schiff, E.A. [ed.] [Syracuse Univ., NY (United States)]; Wagner, S. [ed.] [Princeton Univ., NJ (United States)]; Schropp, R. [ed.] [Utrecht Univ. (Netherlands)]; Matsuda, Akihisa [ed.] [Electrotechnical Lab., Tsukuba (Japan)]; PB: 929 p.; Materials Research Society symposium proceedings, Volume 420
- Country of Publication:
- United States
- Language:
- English
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