Semiconductor device manufacturing: process – Making field effect device having pair of active regions... – On insulating substrate or layer
Reexamination Certificate
2000-02-29
2002-06-04
Nelms, David (Department: 2818)
Semiconductor device manufacturing: process
Making field effect device having pair of active regions...
On insulating substrate or layer
C438S311000
Reexamination Certificate
active
06399429
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method of forming a single-crystal silicon layer and a method of manufacturing a semiconductor device, and a semiconductor device. Specifically, the invention relates to methods suitable for manufacturing a semiconductor device such as an insulated gate field effect transistor using a single-crystal silicon layer grown epitaxially on an insulating substrate for an active region, and relates to such a semiconductor device.
BACKGROUND OF THE INVENTION
A TFT (Thin Film Transistor) is a MOSFET (Metal-oxide-semiconductor field effect transistor) using a single-crystal silicon layer formed on a substrate. As is known in the conventional art, a TFT exhibits an electron mobility several times greater than a transistor utilizing a polysilicon layer, and is suitable for high speed operations (see the following references, R. P. Zingg et al, “First MOS transistors on Insulator by Silicon Saturated Liquid Solution Epitaxy”. IEEE ELECTRON DEVICE LETTERS. VOL. 13, NO. 5, MAY 1992 p294-6., Publication of Examined Japanese Patent Application No. Hei 4-57098, Masakiyo Matsumura, “Thin Film Transistor,” OYO BUTURI, Vol. 65, No. 8 (1996) pp842-848).
There are five deposition methods for forming a single-crystal silicon layer for such a semiconductor element:
(1) growing single-crystal silicon through the decomposition of silane, dichlorosilane, trichlorosilane, silicon tetrachloride at a temperature of about 800-1200° C. in a hydrogen atmosphere at pressures of 100-760 Torr.
(2) forming a silicon epitaxial layer on a single-crystal silicon substrate as a seed by the cooling of a solution of indium and silicon or a solution of indium, gallium and silicon heated to 920-930° C., and then forming a silicon semiconductor layer thereon (see the following references: Reference 1, Soo Hong Lee, “VERY-LOW-TEMPERATURE LIQUID-PHASE EPITAXIAL GROWTH OF SILICON”. MATERIALS LETTERS. Vol. 9. No. 2,3 (January, 1990) pp53-56. Reference 2, R. Bergmann et al, “MOS transistors with epitaxial Si, laterally grown over SiO
2
by liquid phase epitaxy.” J. Applied Physics A, vol. A54, no. 1 p. 103-5. Reference 3, R. P. Zingg et al, “First MOS transistors on Insulator by Silicon Saturated Liquid Solution Epitaxy.” IEEE ELECTRON DEVICE LETTERS. VOL. 13, NO. 5, MAY 1992 p294-6.).
(3) growing silicon epitaxially on a sapphire substrate (see Reference 4, G. A. Garcia, R. E. Reedy, and M. L. Burger, “High-quality CMOS in thin (100 nm) silicon on sapphire,” IEEE ELECTRON DEVICE LETTERS. VOL. 9, pp32-34, January 1988.).
(4) forming a silicon layer on an insulating layer by oxygen ion implantation (see Reference 5, K. Izumi, M. Doken, and H. Ariyoshtl, “CMOS device fabrication on buried SiO
2
layers formed by oxygen implantation into silicon,” Electron. Lett., vol. 14, no. 18, pp593-594, August 1978.).
(5) forming a step on a quartz substrate and then forming thereon a polysilicon layer, which is then heated to 1400° C. or higher by laser beams or a strip heater to form an epitaxial layer on the step formed on the quartz substrate as a seed (see the following references: Reference 6, Seijiro Furukawa, “Graphoepitaxy,” The Transactions of the Institute of Electronics, Information and Communication Engineers, Vol. 66, No. 5, pp486-489. (1983. May). Reference 7, Geis, M. W., et al.: “Crystallographic orientation of silicon on an amorphous substrate using an artificial-relief grating and laser crystallization”, Appl. Phys. Letter, 35, 1, pp71-74 (July 1979). Reference 8, Geis, M. W., et al.: “Silicon graphoepitaxy”, Jpn. J. Appl. Phys., Suppl. 20-1 pp.39-42 (1981).).
According to already known methods, all of the energy required for chemical reactions/single crystal growth is supplied in the form of heat energy (supplied by heating). This causes a problem that the epitaxial-growth temperature cannot be reduced to temperatures considerably lower than about 800° C., more particularly 700° C. This prevents epitaxial growth on, for example, a substrate kept at low temperatures or development of a method for forming a silicon epitaxial layer on a large glass plate which has a relatively low strain point. On the other hand, the method of growing silicon on a step formed on a glass plate as a seed to start epitaxial growth cannot attain the uniform epitaxial growth of silicon at a low temperature.
SUMMARY OF THE INVENTION
The invention has been achieved to overcome the above-described shortcomings. An object of the invention is to provide a method of forming a single-crystal silicon layer and a method of manufacturing a semiconductor device, and a semiconductor device, capable of the uniform epitaxial growth of a silicon layer at a low temperature on a large glass substrate with a relatively low strain point to enable the formation of a high-speed semiconductor element of a large current density thereon.
A method of forming a single-crystal silicon layer of the invention involves the formation of a single-crystal silicon layer on a seeding layer made of a material having a lattice match with a single| crystal silicon layer by CAD (Chemical Vapor Deposition) using a catalyst.
Another method of forming a single-crystal silicon layer of the invention entails the formation of a single-crystal silicon layer on a single-crystal silicon substrate by CAD using a catalyst.
A method of manufacturing a semiconductor device of the invention includes the above-stated step of forming a single-crystal silicon layer, and a subsequent step of manufacturing a semiconductor element through a predetermined treatment of the single-crystal silicon layer.
A semiconductor device of the invention comprises: an insulating substrate; a seeding layer made of a material having a lattice match with single-crystal silicon, the seeding layer formed on the insulating substrate; a single-crystal silicon layer formed on the seeding layer, the single-crystal silicon layer forming a semiconductor element.
According to the present invention, single-crystal silicon is deposited (grown epitaxially) on a seeding layer made of a material having a lattice match with single-crystal silicon (for example, a crystalline sapphire layer) or a single-crystal silicon bulk substrate as a seed by CAD using a catalyst. This enables several outstanding effects and advantages to be obtained, which are as in the followings:
(A) the seeding layer as a seed to start silicon epitaxial growth can be formed by low-pressure CAD (CAD at a low pressure: where the temperature of the substrate is 500-600° C.). In addition, on the seeding layer or a single-crystal silicon substrate, a single-crystal silicon layer can be formed by a low-temperature deposition method, that is, CAD using a catalyst (in which the temperature of the substrate is 100-700° C. and preferably 200-600° C.). This enables the uniform formation of a single-crystal silicon layer on a substrate at a low temperature. Especially, the seeding layer such as a crystalline sapphire layer or a single-crystal silicon substrate makes silicon epitaxial growth easy, having an excellent lattice match with single-crystal silicon particularly because of a lattice constant equal to that of single-crystal silicon.
(B) this makes it possible to use a substrate easily and cheaply available and made of a material of excellent properties, such as a glass substrate having a relatively low strain point, a ceramic substrate or a single-crystal silicon bulk substrate. Of course, a substrate made of quartz glass can be used. Besides, it becomes possible to use a substrate of long dimension more than 100 m or of larger surface area larger than 1 m
2
. This enables the formation of a continuous single-crystal silicon layer on a glass substrate in the form of a roll of wide and long dimensions.
(C) single-crystal silicon can be grown at low temperatures, preventing auto-doping of impurities to simplify the process (specifically, a step of sealing the back of a high-concentration substrate is no longer necessary).
(D) the quality of a silicon epitaxial layer can be improved. Specifically, a decrease in diff
Satou Yuichi
Yagi Hajime
Yamanaka Hideo
Yamoto Hisayoshi
Nelms David
Nhu David
Sonneschein Nath & Rosenthal
Sony Corporation
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