Columbia University

Paul C Van Der Wilt

James S Im

Ui-Jin Chung

Alexander B Limanov

Process and system for processing a thin film sample, as well as at least one portion of the thin film structure are provided. Irradiation beam pulses can be shaped to define at least one line-type beam pulse, which includes a leading portion, a top portion and a trailing portion, in which at least one part has an intensity sufficient to at least partially melt a film sample. Irradiating a first portion of the film sample to at least partially melt the first portion, and allowing the first portion to resolidify and crystallize to form an approximately uniform area therein. After the irradiation of the first portion of the film sample, irradiating a second portion using a second one of the line-type beam pulses to at least partially melt the second portion, and allowing the second portion to resolidify and crystallize to form an approximately uniform area therein. A section of the first portion impacted by the top portion of the first one of the line-type beam pulses is prevented from being irradiated by trailing portion of the second one of the line-type beam pulses.

Processes and systems for laser crystallization processing of film regions on a substrate utilizing a line-type beam, and structures of such film regions

The disclosed systems and method for non-periodic pulse sequential lateral solidification relate to processing a thin film. The method for processing a thin film, while advancing a thin film in a selected direction, includes irradiating a first region of the thin film with a first laser pulse and a second laser pulse and irradiating a second region of the thin film with a third laser pulse and a fourth laser pulse, wherein the time interval between the first laser pulse and the second laser pulse is less than half the time interval between the first laser pulse and the third laser pulse. In some embodiments, each pulse provides a shaped beam and has a fluence that is sufficient to melt the thin film throughout its thickness to form molten zones that laterally crystallize upon cooling. In some embodiments, the first and second regions are adjacent to each other. In some embodiments, the first and second regions are spaced a distance apart.

Systems and methods for non-periodic pulse sequential lateral soldification

In accordance with one aspect, the present invention provides a method for providing polycrystalline films having a controlled microstructure as well as a crystallographic texture. The methods provide elongated grains or single-crystal islands of a specified crystallographic orientation. In particular, a method of processing a film on a substrate includes generating a textured film having crystal grains oriented predominantly in one preferred crystallographic orientation; and then generating a microstructure using sequential lateral solidification crystallization that provides a location-controlled growth of the grains orientated in the preferred crystallographic orientation.

Systems and methods for creating crystallographic-orientation controlled poly-silicon films

A system for preparing a semiconductor film, the system including: a laser source; optics to form a line beam, a stage to support a sample capable of translation; memory for storing a set of instructions, the instructions including irradiating a first region of the film with a first laser pulse to form a first molten zone, said first molten zone having a maximum width (W) and a minimum width (W), wherein the first molten zone crystallizes to form laterally grown crystals; laterally moving the film in the direction of lateral growth a distance greater than about one-half Wand less than W; and irradiating a second region of the film with a second laser pulse to form a second molten zone, wherein the second molten zone crystallizes to form laterally grown crystals that are elongations of the crystals in the first region, wherein laser optics provide Wless than 2&#xd7;W.

Line scan sequential lateral solidification of thin films

A method of processing a polycrystalline film on a substrate includes generating laser pulses, directing the laser pulses through a mask to generate patterned laser beams, each having a length l', a width w&#x2032;, and a spacing between adjacent beams d&#x2032;; irradiating a region of the film with the patterned beams, said beams having an intensity sufficient to melt and to induce crystallization of the irradiated portion of the film, wherein the film region is irradiated n times; and after irradiation of each film portion, translating the film and/or the mask, in the x- and y-directions. The distance of translation in the y-direction is about l&#x2032;/n&#x2212;&#x3b4;, where &#x3b4; is a value selected to overlap the beamlets from one irradiation step to the next. The distance of translation in the x-direction is selected such that the film is moved a distance of about &#x3bb;&#x2032; after n irradiations, where &#x3bb;&#x2032;=w&#x2032;+d&#x2032;.

Single scan irradiation for crystallization of thin films

Systems and methods for non-periodic pulse sequential lateral solidification

A polycrystalline film is prepared by (a) providing a substrate having a thin film disposed thereon, said film capable of laser-induced melting, (b) generating a sequence of laser pulses having a fluence that is sufficient to melt the film throughout its thickness in an irradiated region, each pulse forming a line beam having a predetermined length and width, said width sufficient to prevent nucleation of solids in a portion of the thin film that is irradiated by the laser pulse, (c) irradiating a first region of the film with a first laser pulse to form a first molten zone, said first molten zone demonstrating a variation in width along its length to thereby define a maximum width (W) and a minimum width (W), wherein the first molten zone crystallizes upon cooling to form one or more laterally grown crystals, (d) laterally moving the film in the direction of lateral growth a distance that is greater than about one-half Wand less than W; and (e) irradiating a second region of the film with a second laser pulse to form a second molten zone having a shape that is substantially the same as the shape of the first molten zone, wherein the second molten zone crystallizes upon cooling to form one or more laterally grown crystals that are elongations of the one or more crystals in the first region.

A method of processing a polycrystalline film on a substrate includes generating laser pulses, directing the laser pulses through a mask to generate patterned laser beams, each having a length l', a width w&#x2032;, and a spacing between adjacent beams d&#x2032;; irradiating a region of the film with the patterned beams, said beams having an intensity sufficient to melt and to induce crystallization of the irradiated portion of the film, wherein the film region is irradiated n times; and after irradiation of each film portion, translating the film and/or the mask, in the x- and y-directions. The distance of translation in the y-direction is about l&#x2032;/n-&#x3b4;, where &#x3b4; is a value selected to overlap the beamlets from one irradiation step to the next. The distance of translation in the x-direction is selected such that the film is moved a distance of about &#x3bb;&#x2032; after n irradiations, where &#x3bb;&#x2032;=w&#x2032;+d&#x2032;.

A method of processing a polycrystalline film on a substrate includes generating a plurality of laser beam pulses, positioning the film on a support capable of movement in at least one direction, directing the plurality of laser beam pulses through a mask to generate patterned laser beams; each of said beams having a length l', a width w&#x2032; and a spacing between adjacent beams d&#x2032;, irradiating a region of the film with the patterned beams, said beams having an intensity that is sufficient to melt an irradiated portion of the film to induce crystallization of the irradiated portion of the film, wherein the film region is irradiated n times; and after irradiation of each film portion, translating either the film or the mask, or both, a distance in the x- and y-directions, where the distance of translation in the y-direction is in the range of about 1&#x2032;/n-&#x3b4;, where &#x3b4; is a value selected to form overlapping the beamlets from the one irradiation step to the next, and where the distance of translation in the x-direction is selected such that the film is moved a distance of about &#x3bb;&#x2032; after n irradiations, where &#x3bb;&#x2032;=w&#x2032;+d&#x2032;.

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New York, NY, United States of America

Paul C Van Der Wilt