Single-crystal – oriented-crystal – and epitaxy growth processes; – Processes of growth from liquid or supercritical state – Having moving solid-liquid-solid region
Reexamination Certificate
1998-11-27
2001-11-27
Kunemund, Robert (Department: 1765)
Single-crystal, oriented-crystal, and epitaxy growth processes;
Processes of growth from liquid or supercritical state
Having moving solid-liquid-solid region
C117S044000, C117S904000, C438S779000
Reexamination Certificate
active
06322625
ABSTRACT:
TECHNICAL FIELD
The invention relates to semiconductor materials processing for semiconductor integrated devices.
BACKGROUND OF THE INVENTION
Semiconductor devices can be made in a layer or film of silicon on a quartz or glass substrate, for example. This technology is in use in the manufacture of image sensors and active-matrix liquid-crystal display (AMLCD) devices. In the latter, in a regular array of thin-film transistors (TFT) on an appropriate transparent substrate, each transistor serves as a pixel controller. In commercially available AMLCD devices, the thin-film transistors are formed in hydrogenated amorphous silicon films (a-Si:H TFTs).
In the interest of enhanced switching characteristics of TFTs, polycrystalline silicon has been used instead of amorphous silicon. A polycrystalline structure can be obtained by excimer-laser crystallization (ELC) of a deposited amorphous or microcrystalline silicon film, for example.
However, with randomly crystallized poly-silicon, the results remain unsatisfactory. For small-grained poly-silicon, device performance is hampered by the large number of high-angle grain boundaries, e.g., in the active-channel region of a TFT. Large-grained poly-silicon is superior in this respect, but significant grain-structure irregularities in one TFT as compared with another then result in non-uniformity of device characteristics in a TFT array.
SUMMARY OF THE INVENTION
For improved device characteristics and device uniformity, a lateral solidification technique is applied to a semiconductor film on a substrate. The technique, which may be termed artificially controlled super-lateral growth (ACSLG), involves irradiating a portion of the film with a suitable radiation pulse, e.g. a laser beam pulse, locally to melt the film completely through its entire thickness. When the molten semiconductor material solidifies, a crystalline structure grows from a preselected portion of the film which did not undergo complete melting.
In a preferred first embodiment of the technique, an irradiated structure includes a substrate-supported first semiconductor film, a heat-resistant film on the first semiconductor film, and a second semiconductor film on the heat-resistant film. In this embodiment, both front and back sides of the structure are irradiated with a pulse.
In a preferred second embodiment, lateral solidification is from a first region via a constricted second region to a third region which is intended as a device region. One-sided irradiation is used in this embodiment, in combination with area heating through the substrate.
In a preferred third embodiment, a beam is pulsed repeatedly in forming an extended single-crystal region as a result of laterally stepping a radiation pattern for repeated melting and solidification.
Advantageously, the technique can be used in the manufacture of high-speed liquid crystal display devices, wherein pixel controllers or/and driver circuitry are made in single-crystal or regular/quasi-regular polycrystalline films. Other applications include image sensors, static random-access memories (SRAM), silicon-on-insulator (SOI) devices, and three-dimensional integrated circuit devices.
REFERENCES:
patent: Re. 33836 (1992-03-01), Resor, III et al.
patent: 4234358 (1980-11-01), Celler et al.
patent: 4382658 (1983-05-01), Shields et al.
patent: 4727047 (1988-02-01), Bozler et al.
patent: 4855014 (1989-08-01), Kakimoto et al.
patent: 4870031 (1989-09-01), Suguhara et al.
patent: 4940505 (1990-07-01), Schachameyer et al.
patent: 5061655 (1991-10-01), Ipposhi et al.
patent: 5204659 (1993-04-01), Sarma
patent: 5291240 (1994-03-01), Jain
patent: 5373803 (1994-12-01), Noguchi et al.
patent: 5395481 (1995-03-01), McCarthy
patent: 5409867 (1995-04-01), Asano
patent: 5456763 (1995-10-01), Kaschmitter et al.
patent: 5496768 (1996-03-01), Kudo
patent: 5529951 (1996-06-01), Noguchi et al.
patent: 5591668 (1997-01-01), Maegawa et al.
patent: 5766989 (1998-06-01), Maegawa et al.
patent: 6130009 (2000-10-01), Smith et al.
patent: 2283036 (1990-11-01), None
patent: 6252048 (1994-09-01), None
patent: 6283422 (1994-10-01), None
patent: 7176757 (1995-07-01), None
H.J. Kim and James S. Im, “Grain Boundary Location-Controlled Poly-Si Films for TFT Devices Obtained Via Novel Excimer Laser Process,” Abstracts for Symposium of Materials Research Society, Nov.27 to Dec. 2, 1994, p. 230.
S.D. Brotherton, “Polycrystalline Silicon Thin Film Transistors,” 10 Semicond. Sci. Tech., pp. 721-738 (1995).
H. Watanabe et al., “Crystallization Process of Polycrystalline Silicon by KrF Excimer Laser Annealing,” 33 Japanese J. of Applied Physics Part 1—Regular Papers Short Notes & Review Papers, pp. 4491-98 (1994).
E. Fogarassy et al., “Pulsed Laser Crystallization of Hydrogen-Free a-Si Thin Films for High-Mobility Poly-Si TFT Fabrication,” 56 Applied Physics A—Solids and Surfaces, pp. 365-373 (1993).
Y. Miyata et al, “Low-Temperature Polycrystalline Silicon Thin-Film Transistors for Large-Area Liquid Crystal Display,” 31 Japanese J. of Applied Physics Part 1—Regular Papers Short Notes & Review Papers, pp. 4559-62 (1992).
Baker & Botts LLP
Chen Kin-Chan
Kunemund Robert
The Trustees of Columbia University in the City of New York
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