Sharp Kabushiki Kaisha Corporation

Sharp Laboratories of America, Inc

Other

Agency of Industrial Science and Technology

Masashi Maekawa

Yukihiko Nakata

Naoki Makita

Tadayoshi Miyamoto

Jer-shen Maa

Yoshitaka Yamamoto

Masayoshi Koba

Hiroki Taniyama

Kohei Tanaka

Katunobu Awane

Takashi Funai

Tsukasa Shibuya

Toshiaki Miyajima

Yoshiyuki Itoh

Takamasa Kousai

Norihisa Asano

Michinori Iwai

Keiichi Fukuyama

Disclosed is a semiconductor device which includes a substrate, a thin film transistorhaving a first semiconductor layerA that is supported by the substrate, a thin film diodehaving a second semiconductor layerB that is supported by the substrate, and a metal layerthat is formed between the substrateand the second semiconductor layerB. The first semiconductor layerA is a laterally grown crystalline semiconductor film, and the second semiconductor layerB is a crystalline semiconductor film that contains fine crystal grains. The average surface roughness of the second semiconductor layerB is higher than the average surface roughness of the first semiconductor layerA. Consequently, the optical sensitivity of the TFD is improved and the reliability of the TFT is improved, as compared with those in the conventional semiconductor devices.

Selective recrystallization of semiconductor

A crystalline semiconductor film, the crystalline semiconductor film being formed over an insulative substrate, and including semiconductor crystal grains laterally grown along a surface of the insulative substrate, wherein the laterally-grown semiconductor crystal grains are in contact with each other at grain boundaries, and a distance between adjacent grain boundaries is equal to or smaller than two times a lateral growth distance of the semiconductor crystal grains.

Crystalline semiconductor film and production method thereof, and semiconductor device and production method thereof

A TFT fabricated from a single crystal grain, and fabrication method has been provided. A large crystal grain is made by precise control of annealment, transition metal concentration, the density of transition metal nucleation sites, and the distance between nucleation sites. In one aspect of the invention, a diffusion layer permits the continual delivery of transition metal at a rate that both supports the lateral growth of di-silicide, and large distances between nucleation sites.

Single crystal TFT from continuous transition metal delivery method

A method has been provided to form a sheet of large grain crystallized silicon, in an early stage of transistor production, before the areas of the source and drain are defined. The method takes advantage of high annealing temperatures and transition metals to speed the lateral growth of silicide. By using higher temperatures, the number of amorphous enclaves is minimized and the transition metal nucleation site can be made small. A small transition metal nucleation site, in turn, can be more easily located near the center of a transistor, or where it is convenient. After annealing, the areas close to the silicide nucleation site are transformed into polycrystalline with a high electron mobility, desirable for the formation of source/drain and channel regions. Silicide products, away from the transistor active areas, are etched away when the area of the source and drain are defined. A product by process using the method of the above-described invention is also provided.

Thin film transistor in metal-induced crystallized region formed around a transition metal nucleus site

A method for annealing amorphous silicon film to produce polycrystalline film suitable for thin-film transistors fabricated on glass substrates is provided. The method involves using the selective location of nickel on a predetermined region of silicon to define the pattern of the lateral growth front as the silicon is crystallized. The method defines the resistivity of the silicide formed. The method also defines a specific range of nickel thicknesses to form the nickel silicide. A minimum thickness ensures that a continuous layer of nickel silicide exists on the growth front to promote an isotropic lateral growth front to form a crystalline film having high electron mobility. A maximum thickness limit reduces the risk of nickel silicide enclaves in the crystalline film to degrade the leakage current. Strategic placement of the nickel helps prevent nickel silicide contamination of the transistor channel regions, which degrade the leakage current. A TFT polycrystalline film is also provided made by the above mentioned process of using a defined thickness, silicide resisitivity, and placement of nickel on amorphous silicon to form a silicide which induces a controlled crystallization growth front.

Selective silicide thin-film transistor having polysilicon active layers with crystallizing metal agent introduced only in the source/drain regions

Selected site, metal-induced, continuous crystallization method

A method for annealing amorphous silicon film to produce polycrystalline film suitable for thin-film transistors fabricated on glass substrates is provided. The method involves using nickel to help induce the crystallization. The method also uses a high temperature, for a short period of time, to anneal the amorphous silicon. A one-step annealing process implants nickel ions, having a dosage of approximately 1&times;10,ions/cm,, into the silicon before annealing. A two-step annealing process is also provided in which a thin nickel film is put in close proximity to the amorphous silicon film. A first, low temperature, anneal converts a portion of the films to nickel silicide. A second, high temperature, anneal uses the silicide to induce the amorphous film to crystallize. A TFT polycrystalline film made by the above mentioned process of using nickel and, either a one, or two-step high temperature annealing to induce crystallization is also provided.

Method of forming polycrystalline film by steps including introduction of nickel and rapid thermal anneal

In a fabrication of a semiconductor device, an amorphous semiconductor film is first formed on a substrate having an insulating surface. Then, a minute amount of catalyst elements for accelerating crystallization of the amorphous semiconductor film is supplied to at least a portion of a surface of the amorphous semiconductor film. A heat treatment is further conducted so that the supplied catalyst elements are diffused into the amorphous semiconductor film. Thus, the catalyst elements are introduced uniformly into the amorphous semiconductor film in a very minute amount or at a low concentration, resulting in polycrystallization of at least a portion of the amorphous semiconductor film. Utilizing the thus obtained crystalline semiconductor film on the substrate surface as an active region, a semiconductor device such as a TFT is fabricated. The introduction of the catalyst elements are conducted by various methods such as: a formation of a film containing a minute amount of the catalyst elements; application of a solution containing the catalyst elements in several spin coating cycles; diffusion of the catalyst elements through a buffer layer; dipping into a solution in which the catalyst elements are dissolved or dispersed; or formation of a plating layer containing the catalyst elements.

Method for fabricating thin film transistors

A method for annealing amorphous silicon film to produce polycrystalline film suitable for thin-film transistors fabricated on glass substrates is provided. The method involves using nickel to help induce the crystallization. The method also uses a high temperature, for a short period of time, to anneal the amorphous silicon. A one-step annealing process implants nickel ions, having a dosage of approximately 1.times.10.sup.15 ions/cm.sup.2, into the silicon before annealing. A two-step annealing process is also provided in which a thin nickel film is put in close proximity to the amorphous silicon film. A first, low temperature, anneal converts a portion of the films to nickel silicide. A second, high temperature, anneal uses the silicide to induce the amorphous film to crystallize. A TFT polycrystalline film made by the above mentioned process of using nickel and, either a one, or two-step high temperature annealing to induce crystallization is also provided.

Thin-film transistor polycrystalline film formation by nickel induced,

A method for rapid thermally annealing a thin amorphous film on a transparent substrate with the use of a radiation absorption film is provided. Unlike a transmissive silicon thin film, or transparent substrate, the metal absorptive film has excellent radiation absorption characteristics. When a radiation absorption layer is added to the substrate it is possible to rapidly anneal an amorphous silicon film with convention IC process radiation lamps. The metal absorption film also acts to conduct the heat to the amorphous silicon. The control provided by the choice of metal material, metal thickness, the oxidation of the metal surface, and the heat and duration of the RTA process provide unique opportunities to control the crystallization process. Polysilicon made by the above-described method has the potential of high electron mobility and low production costs. A thin-film structure for use in a TFT, made through the above-described method, is also provided.

Rapid thermal annealing with absorptive layers for thin film transistors

Selective silicide thin-film transistor and method for same

The semiconductor device of invention includes: a substrate having an insulating surface; and an element region formed by crystallizing an amorphous silicon film, the element region being provided on the insulating surface of the substrate. In the semiconductor device, the element region is constituted by a laterally crystallized region formed by crystallizing the amorphous silicon film from a linearly crystallized region crystallized by a selective introduction of catalyst elements for promoting a crystallization of the amorphous silicon film to a region surrounding the linearly crystallized region by performing a heat-treatment, and a concentration of the catalyst elements in at least one of the laterally crystallized region and the linearly crystallized region is controlled by a line width of an introduction setting region having a linear planar pattern, the line width being set so as to selectively introduce the catalyst elements.

Semiconductor device and method for fabricating the same

Improvements in a method for performing a monocrystallizing operation through the application of energy beams upon a non-monocrystalline thin-film of non-crystalline or polycrystalline material formed on a non-crystalline insulating film. The resulting superior monocrystalline thin-film has a crystal direction coinciding with that of the monocrystalline silicon base-plate and is formed on the insulating film even if the insulating film is as thick as 4 .mu.m. The thin-film is sufficiently covered between the active layers of a three-dimensional circuit element on the monocrystalline silicon base plate. '

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Nara, Japan

Masashi Maekawa