Abstract: A method is provided to produce thin film transistors (TFTs) on polycrystalline films having a single predominant crystal orientation. A layer of amorphous silicon is deposited over a substrate to a thickness suitable for producing a desired crystal orientation. Lateral-seeded excimer laser annealing (LS-ELA) is used to crystallize the amorphous silicon to form a film with a preferred crystal orientation. The crystallized film is then polished to a desired thickness. A gate is formed overlying the polycrystalline film. The polycrystalline film is doped to produce source and drain regions.

Abstract: A substrate and a method for fabricating variable quality substrate materials are provided. The method comprises: selecting a first mask having a first mask pattern; projecting a laser beam through the first mask to anneal a first area of semiconductor substrate; creating a first condition in the first area of the semiconductor film; selecting a second mask having a second mask pattern; projecting the laser beam through the second mask to anneal a second area of the semiconductor film; and, creating a second condition in the second area of the semiconductor film, different than the first condition. More specifically, when the substrate material is silicon, the first and second conditions concern the creation of crystalline material with a quantitative measure of lattice mismatch between adjacent crystal domains.

Abstract: A method has been provided for forming a polycrystalline silicon (p-Si) film with a small amount of hydrogen. Such a film has been found to have excellent sheet resistance, and it is useful in the fabrication of liquid crystal display (LCD) panels made from thin film transistors (TFTs). The low hydrogen content polycrystalline silicon films are made from introducing a small amount of hydrogen gas, with Ar, during the sputter deposition of an amorphous silicon film. The hydrogen content in the film is regulated by controlling the deposition temperatures and the volume of hydrogen in the gas feed during the sputter deposition. The polycrystalline silicon film results from annealing the low hydrogen content amorphous silicon film thus formed.

Abstract: A method is provided for maintaining a planar surface as crystal grains are laterally grown in the fabrication of crystallized silicon films. The method comprises: forming a film of amorphous silicon with a surface and a plurality of areas; irradiating each adjacent areas of the silicon film with a first sequence of laser pulses; and, in response to the first sequence of laser pulses, controlling the planarization of the silicon film surface between adjacent areas of the silicon film as the crystal grains are laterally grown. By controlling the number of laser pulses in the sequence, the temporal separation between pulses, and the relative intensity of the pulses, the lateral growth length characteristics of the crystal grains can be traded against the silicon film flatness. A silicon film formed by a pulsed laser sequence crystallization process is also provided.

Abstract: A method is provided to produce thin polycrystalline films having a single predominant crystal orientation. The method is well suited to the production of films for use in production of thin film transistors (TFTs). A layer of amorphous silicon is deposited over a substrate to a thickness suitable for producing a desired crystal orientation. Lateral-seeded excimer laser annealing (LS-ELA) is used to crystallize the amorphous silicon to form a film with a preferred crystal orientation. The crystallized film is then polished to a desired thickness for subsequent processing.

Abstract: A method has been provided for etching adjoining layers of indium tin oxide (ITO) and silicon in a single, continuous dry etching process. A conventional dry etching gas, such as HI, is used to etch ITO using RF or plasma energy. When the silicon layer underlying the ITO layer is reached, oxygen or nitrogen is added to etching gas to improve the selectivity of ITO to silicon. In some aspects of the invention an etch-stop layer is formed in the silicon layer. A specific example of fabricating a bottom gate thin film transistor (TFT) is also provided where adjoining layers of source metal, ITO, and channel silicon are etched in the same dry etch step.

Abstract: A system and method are provided for laser irradiating a semiconductor substrate using a multi-pattern mask. The method comprises: exposing a semiconductor substrate to laser light projected through a multi-pattern mask; advancing the mask and substrate in a first direction to sequentially expose adjacent areas of the substrate to each of the mask patterns in a first predetermined order; and, advancing the mask and substrate in a second direction, opposite the first direction, to sequentially expose adjacent areas of the substrate to each of the mask patterns in the first order. In one aspect, the method further comprises: forming a multi-pattern mask having a first plurality patterns aligned in the first order with respect to the first direction and a second plurality of patterns, corresponding to the first plurality of patterns, aligned in the first order with respect to the second direction.

Abstract: A substrate and a method for fabricating variable quality substrate materials are provided. The method comprises: selecting a first mask having a first mask pattern; projecting a laser beam through the first mask to anneal a first area of semiconductor substrate; creating a first condition in the first area of the semiconductor film; selecting a second mask having a second mask pattern; projecting the laser beam through the second mask to anneal a second area of the semiconductor film; and, creating a second condition in the second area of the semiconductor film, different than the first condition. More specifically, when the substrate material is silicon, the first and second conditions concern the creation of crystalline material with a quantitative measure of lattice mismatch between adjacent crystal domains. For example, the lattice mismatch between adjacent crystal domains can be measured as a number of high-angle grain boundaries per area.

Abstract: A 1:1 laser projection system and method are provided for laser irradiating a semiconductor film. The method comprises: exposing a mask to a beam of laser light; projecting laser light passed through the mask by a factor of one; exposing the area of a semiconductor film to the projected laser light having a first energy density; exposing an area of semiconductor film to a lamp light having a second energy density; and, summing the first and second energy densities to heat the area of film. When the semiconductor film is silicon, the film heating typically entails melting, and then, crystallizing the film. In some aspects of the method, the lamp is an excimer lamp having a wavelength of less than 550 nanometers (nm), and the laser is an excimer laser having a wavelength of less than 550 nm. In some aspects, the lamp is mounted to expose the bottom surface of the film including an area underlying the area being laser irradiated.

Abstract: A method is provided for crystallizing a silicon film in liquid crystal display (LCD) fabrication. The method comprises: forming an amorphous silicon film having a thickness in the range of 100 to 1000 Angstroms (Å); irradiating the silicon film with a laser pulse having a pulse width of 50 nanoseconds (ns) or greater, as measured at the full-width-half-maximum (FWHM), using a beamlet width in the range of 3 to 20 microns; and, in response to irradiating the silicon film, laterally growing crystal grains. In one example, irradiating the silicon film may include irradiating with a pulse having a pulse width in the range between 30 and 300 ns FWHM, and an energy density in the range from 200 to 1300 millijoules per square centimeter (mJ/cm2).

Abstract: The invention provides an apparatus for reducing, or eliminating, ambient air in connection with an excimer laser annealing process. Nozzles are provided to direct a flow of gas, preferably helium, neon, argon or nitrogen, at a region overlying the target area of an amorphous silicon layer deposited on an LCD substrate. The nozzles direct a flow of gas at sufficient pressure and flow rate to remove ambient air from the region overlying the target area. With the ambient air, especially oxygen, removed, the laser can anneal the amorphous silicon to produce polycrystalline silicon with less oxygen contamination. In a preferred embodiment, an exhaust system is also provided to remove the gas.

Abstract: A method is provided to optimize the channel characteristics of thin film transistors (TFTs) on polysilicon films. The method is well suited to the production of TFTs for use as drivers on liquid crystal display devices. Regions of polycrystalline silicon can be formed with different predominant crystal orientations. These crystal orientations can be selected to match the desired TFT channel orientations for different areas of the device. The crystal orientations are selected by rotating a mask pattern to a different orientation for each desired crystal orientation. The mask is used in connection with lateral crystallization ELA processes to crystallize deposited amorphous silicon films.

Abstract: A system and method are provided to sequentially deposit a silicon dioxide base coat barrier layer adjacent a thin silicon film, to minimize the formation of water and —OH radicals. Both the base coat and thin silicon films are sputter to eliminate hydrogen chemistries. Further, the sputter processes are conducted sequentially, without breaking the vacuum seat to minimize the absorption of water in the base coat layer that conventionally occurs between deposition steps. This process eliminates the total number of process steps required, as there is no longer a need for furnace annealing the base coat before the deposition of the thin silicon film, and no longer a need for a dehydrogenation annealing step after the deposition of the thin silicon film.

Abstract: The invention provides an apparatus for reducing, or eliminating, ambient air in connection with an excimer laser annealing process. Nozzles are provided to direct a flow of gas, preferably helium, neon, argon or nitrogen, at a region overlying the target area of an amorphous silicon layer deposited on an LCD substrate. The nozzles direct a flow of gas at sufficient pressure and flow rate to remove ambient air from the region overlying the target area. With the ambient air, especially oxygen, removed, the laser can anneal the amorphous silicon to produce polycrystalline silicon with less oxygen contamination. In a preferred embodiment, an exhaust system is also provided to remove the gas.

Abstract: A method is provided to optimize the channel characteristics of thin film transistors (TFTs) on polysilicon films. The method is well suited to the production of TFTs for use as drivers on liquid crystal display devices. The method is also well suited to the production of other devices using polysilicon films. Regions of polycrystalline silicon can be formed with different predominant crystal orientations. These crystal orientations can be selected to match the desired TFT channel orientations for different areas of the device. The crystal orientations are selected by selecting different mask patterns for each of the desired crystal orientation. The mask patterns are used in connection with lateral crystallization ELA processes to crystallize deposited amorphous silicon films.

Abstract: A method is provided to produce thin film transistors (TFTs) on polycrystalline films having a single predominant crystal orientation. A layer of amorphous silicon is deposited over a substrate to a thickness suitable for producing a desired crystal orientation. Lateral-seeded excimer laser annealing (LS-ELA) is used to crystallize the amorphous silicon to form a film with a preferred crystal orientation. A gate is formed overlying the polycrystalline film. The polycrystalline film is doped to produce source and drain regions.

Abstract: The present invention concerns a method of forming multi-layers such as base-coat and active layers for TFTs. In accordance with the preferred embodiment of the present invention, a first layer is formed on a transparent substrate using a physical vapor deposition. And a second layer is sequentially formed using a physical vapor deposition on the first layer without breaking vacuum.

Abstract: A method is provided to optimize the channel characteristics of thin film transistors (TFTs) on polysilicon films. The method is well suited to the production of TFTs for use as drivers on liquid crystal display devices. Regions of polycrystalline silicon can be formed with different predominant crystal orientations. These crystal orientations can be selected to match the desired TFT channel orientations for different areas of the device. The crystal orientations are selected by rotating a mask pattern to a different orientation for each desired crystal orientation. The mask is used in connection with lateral crystallization ELA processes to crystallize deposited amorphous silicon films.

Abstract: A method is provided to produce thin film transistors (TFTs) on polycrystalline films having a single predominant crystal orientation. A layer of amorphous silicon is deposited over a substrate to a thickness suitable for producing a desired crystal orientation. Lateral-seeded excimer laser annealing (LS-ELA) is used to crystallize the amorphous silicon to form a film with a preferred crystal orientation. A gate is formed overlying the polycrystalline film. The polycrystalline film is doped to produce source and drain regions.

Abstract: A system and method are provided to sequentially deposit a silicon dioxide base coat barrier layer adjacent a thin silicon films, to minimize the formation of water and —OH radicals. Both the base coat and thin silicon films are sputter deposited to eliminate hydrogen chemistries. Further, the sputter processes are conducted sequentially, with breaking the vacuum seal, to minimize the absorption of water in the base coat layer that conventionally occurs between deposition steps. This process eliminates the total number of process steps required, as there is no longer a need for furnace annealing the base coat before the deposition of the thin silicon film, and no longer a need for a dehydrogenation annealing step after the deposition of the thin silicon film.