Abstract: A recessed-gate thin-film transistor (RG-TFT) with a self-aligned lightly doped drain (LDD) is provided, along with a corresponding fabrication method. The method deposits an insulator overlying a substrate and etches a trench in the insulator. The trench has a bottom and sidewalls. An active silicon (Si) layer is formed overlying the insulator and trench, with a gate oxide layer over the active Si layer. A recessed gate electrode is then formed in the trench. The TFT is doped and LDD regions are formed in the active Si layer overlying the trench sidewalls. The LDD regions have a length that extends from a top of the trench sidewall, to the trench bottom, with a doping density that decreases in response to the LDD length. Alternately stated, the LDD length is directly related to the depth of the trench.

Abstract: The invention provides a fluorocarbon coating having a reduced surface energy that has low susceptibility to molecular and particulate contamination. The fluorocarbon coating is stable and functional in vacuum. The fluorocarbon coating is stable to chemical solvents, cryogenic temperatures, and temperatures as high as 400° C. The fluorocarbon coating may be deposited as a thin film or produced as a modification to a surface of optical instruments without significant alteration of the optical characteristics. The fluorocarbon coating may reside on a textured substrate or include texturing within the process to further enhance the contamination resistant qualities of the treated surface. The fluorocarbon coating may be graded in composition throughout the coating layer. The invention can be used on surfaces that operate in aerospace environments and in dusty environments where contamination is an important consideration.

Abstract: A method is provided for crystallizing a semiconductor film using a buried seed one-shot interlevel crystallization process. The method forms a first semiconductor film having a crystallographic structure, overlying a transparent substrate. An insulator layer is formed overlying the first semiconductor film, and an opening is formed in the insulator layer, which exposes a portion of a first semiconductor film top surface. Then, a second semiconductor film with an amorphous structure is formed overlying the insulator layer. Typically, the first and second semiconductor films are Si, and the insulator is often an oxide or nitride. The second semiconductor film is laser annealed. In one aspect, the annealing is accomplished with a single laser shot. In response to the laser annealing, the second semiconductor film is completely melted and the first semiconductor film is partially melted. Using unmelted first semiconductor film as a seed, the second semiconductor film is crystallized.

Abstract: A recessed-gate thin-film transistor (RG-TFT) with a self-aligned lightly doped drain (LDD) is provided, along with a corresponding fabrication method. The method deposits an insulator overlying a substrate and etches a trench in the insulator. The trench has a bottom and sidewalls. An active silicon (Si) layer is formed overlying the insulator and trench, with a gate oxide layer over the active Si layer. A recessed gate electrode is then formed in the trench. The TFT is doped and LDD regions are formed in the active Si layer overlying the trench sidewalls. The LDD regions have a length that extends from a top of the trench sidewall, to the trench bottom, with a doping density that decreases in response to the LDD length. Alternately stated, the LDD length is directly related to the depth of the trench.

Abstract: Methods for processing an amorphous silicon thin film sample into a polycrystalline silicon thin film are disclosed.

Abstract: Methods for processing an amorphous silicon thin film sample into a polycrystalline silicon thin film are disclosed.

Abstract: A high-quality isotropic polycrystalline silicon (poly-Si) and a method for fabricating high quality isotropic poly-Si film are provided. The method includes forming a film of amorphous silicon (a-Si) and using a MISPC process to form poly-Si film in a first area of the a-Si film. The method then anneals a second area, included in the first area, using a Laser-Induced Lateral Growth (LILaC) process. In some aspects, a 2N-shot laser irradiation process is used as the LILaC process. In some aspects, a directional solidification process is used as the LILaC process. In response to using the MISPC film as a precursor film, the method forms low angle grain boundaries in poly-Si in the second area.

Abstract: Systems and methods for reducing a surface roughness of a polycrystalline or single crystal thin film produced by the sequential lateral solidification process are disclosed.

Abstract: A system and method are provided for reducing film surface protrusions in the fabrication of LILAC films. The method comprises: forming an amorphous film with a first thickness; annealing the film using a LILAC process, with beamlets having a width in the range of 3 to 10 microns; in response to annealing, forming protrusions on the film surface; optionally oxidizing the film surface; thinning the film; and, in response to thinning the film, smoothing the film surface. Typically, the film surface is smoothed to a surface flatness of 300 ?, or less. In some aspects of the method, oxidizing the film surface includes oxidizing the film surface to a depth. Then, thinning the film includes thinning the film to a third thickness equal to the first thickness minus the depth.

Abstract: Systems and methods for reducing a surface roughness of a polycrystalline or single crystal thin film produced by the sequential lateral solidification process are disclosed.

Abstract: A mask with sub-resolution aperture features and a method for smoothing an annealed surface using a sub-resolution mask pattern are provided. The method comprises: supplying a laser beam having a first wavelength; supplying a mask with a first mask section having apertures with a first dimension and a second mask section with apertures having a second dimension, less than the first dimension; applying a laser beam having a first energy density to a substrate region; melting a substrate region in response to the first energy density; crystallizing the substrate region; applying a diffracted laser beam to the substrate region; and, in response to the diffracted laser beam, smoothing the substrate region surface. In some aspects of the method, applying a diffracted laser beam to the substrate area includes applying a diffracted laser beam having a second energy density, less than the first energy density, to the substrate region.

Abstract: A mask with sub-resolution aperture features and a method for smoothing an annealed surface using a sub-resolution mask pattern are provided. The method comprises: supplying a laser beam having a first wavelength; supplying a mask with a first mask section having apertures with a first dimension and a second mask section with apertures having a second dimension, less than the first dimension; applying a laser beam having a first energy density to a substrate region; melting a substrate region in response to the first energy density; crystallizing the substrate region; applying a diffracted laser beam to the substrate region; and, in response to the diffracted laser beam, smoothing the substrate region surface. In some aspects of the method, applying a diffracted laser beam to the substrate area includes applying a diffracted laser beam having a second energy density, less than the first energy density, to the substrate region.

Abstract: A process of lateral crystallization comprises providing a silicon film on a substrate surface, exposing a localized substrate region at the substrate surface to a laser heating source, and annealing a portion of the silicon film in thermal contact with the localized substrate region by exposing the silicon film to a low-fluence optical annealing source.

Abstract: Accordingly, a method of suppressing energy spikes is provided comprising projecting a laser beam through a mask having a slit pattern comprising a corner region with edges, and a blocking feature with the corner region to reduce energy spikes projected on a substrate. An alternative method is provided, wherein the corner region is modified such that it is replaced by a more tapered shaped region, preferably a triangle. Also provided, are a variety of mask designs incorporating both corner regions, with and without one or more blocking features, and triangular regions, with or without one or more blocking features. The mask designs provide examples of mask modifications that may be used to reduce energy spikes.

Abstract: Methods for processing an amorphous silicon thin film sample into a polycrystalline silicon thin film are disclosed.

Abstract: A process of lateral crystallization is provided for increasing the lateral growth length (LGL). A localized region of the substrate is heated for a short period of time. While the localized region of the substrate is still heated, a silicon film overlying the substrate is irradiated to anneal the silicon film to crystallize a portion of the silicon film in thermal contact with the heated substrate region. A CO2 laser may be used as a heat source to heat the substrate, while a UV laser or a visible spectrum laser is used to irradiate and crystallize the film.

Abstract: A process of lateral crystallization is provided for increasing the lateral growth length (LGL). A localized region of the substrate is heated for a short period of time. While the localized region of the substrate is still heated, a silicon film overlying the substrate is irradiated to anneal the silicon film to crystallize a portion of the silicon film in thermal contact with the heated substrate region. A CO2 laser may be used as a heat source to heat the substrate, while a UV laser or a visible spectrum laser is used to irradiate and crystallize the film.

Abstract: Methods for processing an amorphous silicon thin film sample into a polycrystalline silicon thin film are disclosed.

Abstract: A wide-slit lateral growth projection mask, projection system, and corresponding crystallization process are provided. The mask includes an opaque region with at least one a transparent slit in the opaque region. The slit has a width in the range of 10X to 50X micrometers, with respect to a X:1 demagnification system, and a triangular-shaped slit end. The triangular-shaped slit end has a triangle height and an aspect ratio in the range of 0.5 to 5. The aspect ratio is defined as triangle height/slit width. In some aspects, the triangular-shaped slit end includes one or more opaque blocking features. In another aspect, the triangular-shaped slit end has stepped-shaped sides. The overall effect of the mask is to promote uniformly oriented grain boundaries, even in the film areas annealed under the slit ends.

Abstract: A high-quality isotropic polycrystalline silicon (poly-Si) and a method for fabricating high quality isotropic poly-Si film are provided. The method includes forming a film of amorphous silicon (a-Si) and using a MISPC process to form poly-Si film in a first area of the a-Si film. The method then anneals a second area, included in the first area, using a Laser-Induced Lateral Growth (LILaC) process. In some aspects, a 2N-shot laser irradiation process is used as the LILaC process. In some aspects, a directional solidification process is used as the LILaC process. In response to using the MISPC film as a precursor film, the method forms low angle grain boundaries in poly-Si in the second area.