National Semiconductor Corporation

Spectralus Corporation

Stepan Essaian

Andrei V Shchegrov

Abdalla Aly Naem

Dzhakhangir V Khaydarov

Daniel Henry Rosenblatt

A compact, optically-pumped solid-state microchip laser device uses efficient nonlinear intracavity frequency conversion for obtaining low-cost green and blue laser sources. The laser includes a solid-state gain medium, such as Nd:YVO, and a nonlinear crystal. The nonlinear crystal is formed of periodically poled lithium niobate or periodically poled lithium tantalate, and the crystal is either MgO-doped, ZnO-doped, or stoichiometric to ensure high reliability. The nonlinear crystal provides efficient frequency doubling to translate energy from an infrared pump laser beam into the visible wavelength range. The laser device is assembled in a package having an output aperture for the output beam and being integrated with an optical bench accommodating a laser assembly. The package encloses and provides heat sinking for the semiconductor diode pump laser, the microchip laser cavity assembly, the optical bench platform, and electrical leads.

Efficient and compact visible microchip laser source with periodically poled nonlinear materials

A compact optically-pumped solid-state laser designed for efficient nonlinear intracavity frequency conversion into desired wavelengths using periodically poled nonlinear crystals. These crystals contain dopants such as MgO or ZnO and/or have a specified degree of stoichiometry that ensures high reliability. The laser includes a solid-state gain media chip, such as Nd:YVO, which also provides polarization control of the laser; and a periodically poled nonlinear crystal chip such as PPMgOLN or PPZnOLT for efficient frequency doubling of the fundamental infrared laser beam into the visible wavelength range. The described designs are especially advantageous for obtaining low-cost green and blue laser sources. Also described design of the continuously operated laser with an electro-optic element for modulation of the intensity of the laser output at frequencies up to hundred of megahertz. Such modulation is desired for various applications, including compact projectors with high resolution.

Compact and efficient visible laser source with high speed modulation

A compact and efficient ultraviolet laser source based on a optically-pumped solid-state or fiber laser that produces near-infrared output light suitable for nonlinear frequency conversion. The infrared laser output is frequency tripled or quadrupled to produce light in the ultraviolet wavelength range (200 nm to 400 nm). The novel technology is the use of highly efficient periodically poled nonlinear crystals, such as stoichiometric and MgO-doped lithium tantalate and lithium niobate. As opposed to conventional frequency-converted UV laser sources, which have high power consumption, high cost, and low efficiency, the laser sources of this invention utilize high efficiency nonlinear conversion provided by periodically poled materials and allow lower-cost architectures without additional focusing lenses, high power pump diodes, etc.

Compact, efficient and robust ultraviolet solid-state laser sources based on nonlinear frequency conversion in periodically poled materials

A compact optically-pumped solid-state laser designed for efficient nonlinear intracavity frequency conversion into desired wavelengths using periodically poled nonlinear crystals. These crystals contain dopants such as MgO or ZnO and/or have a specified degree of stoichiometry that ensures high reliability. The laser includes a solid-state gain media chip, such as Nd:YVO, which also provides polarization control of the laser; and a periodically poled nonlinear crystal chip such as PPMgOLN or PPZnOLT for efficient frequency doubling of the fundamental infrared laser beam into the visible wavelength range. The described designs are especially advantageous for obtaining low-cost green and blue laser sources.

Compact solid-state laser with nonlinear frequency conversion using periodically poled materials

A compact solid-state laser array for nonlinear intracavity frequency conversion into desired wavelengths using periodically poled nonlinear crystals. The crystals contain dopants such as MgO and/or have a specified stoichiometry. A preferred embodiment comprises a microchip laser cavity that includes a solid-state gain chip, such as Nd:YVO, which also provides polarization control of the laser; and a periodically poled nonlinear crystal chip such as PPMgOLN, for efficient frequency doubling of a infrared laser pump beam into the visible wavelength range. The described designs are especially advantageous for obtaining low-cost green and blue laser sources. The use of such high-efficiency pumps and nonlinear materials allows scaling of a compact, low-cost architecture to provide high output power levels in the blue/green wavelength range.

Solid-state laser arrays using nonlinear frequency conversion in periodically poled materials

Compact efficient and robust ultraviolet solid-state laser sources based on nonlinear frequency conversion in periodically poled materials

A process for reducing the poling field of congruent LiNbOand LiTaOcrystal-based nonlinear optical devices and for the production of domain structures with precise reproducibility of the main parameters by depositing a thin layer of a stoichiometric LiNbOfilm on the Z-face of a congruent LiNbOor LiTaOwafer. A new domain nucleation, evolution and stabilization process is provided to afford a uniform, short period domain superstructure for the conversion of near infra-red light to near ultraviolet, blue and green light.

Method for the fabrication of periodically poled Lithium Niobate and Lithium Tantalate nonlinear optical components

Isolation of a heterojunction bipolar transistor device in an integrated circuit is accomplished by forming the device within a trench in dielectric material overlying single crystal silicon. Precise control over the thickness of the initially-formed dielectric material ultimately determines the depth of the trench and hence the degree of isolation provided by the surrounding dielectric material. The shape and facility of etching of the trench may be determined through the use of etch-stop layers and unmasked photoresist regions of differing widths. Once the trench in the dielectric material is formed, the trench is filled with selectively and/or nonselectively grown epitaxial silicon. The process avoids complex and defect-prone deep trench masking, deep trench silicon etching, deep trench liner formation, and dielectric reflow steps associated with conventional processes.

Process for forming damascene-type isolation structure for integrated circuit

A silicon-germanium alloy of high crystal quality and containing uniform concentrations of dopant and germanium is formed by applying laser energy to a doped amorphous/polysilicon germanium layer overlying epitaxial silicon. Energy transferred from the laser beam causes melting of the germanium and the underlying silicon, resulting in diffusion of germanium and dopant into the melted silicon. Subsequent cooling and crystallization of the silicon/germanium/dopant melt produces a high quality crystal lattice uniformly incorporating germanium and dopant within its structure. Efficient energy transfer from the laser beam to the underlying germanium and silicon may be promoted by patterning an anti-reflective coating over the amorphous/polysilicon doped germanium prior to exposure to laser radiation. The process is particularly suited for forming the silicon-germanium base of a heterojunction bipolar transistor device.

Formation of doped silicon-germanium alloy utilizing laser crystallization

Process for forming damascene-type isolation structure for BJT device formed in trench

Extremely high dopant concentrations are uniformly introduced into a semiconductor material by laser annealing aided by an anti-reflective coating (ARC). A spin-on-glass (SOG) film containing dopant is formed on top of the semiconductor material. An ARC is then formed over the doped SOG layer. Application of radiation from an excimer laser to the ARC heats and melts the doped SOG film and the underlying semiconductor material. During this melting process, dopant from the SOG film diffuses uniformly within the semiconductor material. Upon removal of the laser radiation, the semiconductor material cools and crystallizes, evenly incorporating the diffused dopant within its lattice structure. The ARC suppresses reflection of the laser by the doped material, promoting efficient transfer of energy from the laser to heat and melt the underlying doped layer and semiconductor material. The present process is especially suited for introducing extremely high levels of conductivity-altering dopant (10  atoms/cm ) into the polysilicon emitter of a heterojunction bipolar transistor device.

Selective high concentration doping of semiconductor material utilizing laser annealing

Ion implantation of fluorine into SiO.sub.2 films results in formation of a dielectric material having a dielectric constant K.ltoreq.3.2. High energies associated with ion implantation permit stable introduction of high concentrations of fluorine within silicon oxide, without giving rise to problems of fluorine outgassing and water absorption associated with conventional FSG deposition techniques. Relatively thick FSG layers conventionally formed by CVD may be sandwiched between implanted FSG liner films formed in accordance with the present invention. Such a combination would reduce the dielectric constant of the dielectric structure as a whole while providing a barrier to fluorine diffusion, without consuming the processing time required to implant an entire dielectric layer.

F ion implantation into oxide films to form low-K intermetal dielectric

Stable suicides are formed utilizing excimer laser crystallization in place of a conventional second high temperature rapid thermal processing annealing step. Specifically, thermally unstable silicide having a metal-rich surface layer is conventionally formed utilizing deposition of refractory metal followed by low temperature annealing. After removal of unreacted refractory metal, an amorphous silicon film is deposited on top of the unstable silicide and exposed to radiation from an excimer laser, such that the amorphous silicon melts, reacts with refractory metal from the underlying unstable silicide, and reforms as thermally stable silicide evidencing low electrical resistance.

Fabrication of silicides by excimer laser annealing of amorphous silicon

A new ferroelectric memory element is disclosed. The ferroelectric material exhibits little polarization fatigue up to 10.sup.12 switching cycles, long retention and minimal tendency to imprint, producing a nonvolatile, nondestructive readout memory element having low saturation voltage for switching. The memory element can be manufactured using conventional CMOS transistor technology and may include a SrBi.sub.2 Ta.sub.2 O.sub.9 ferroelectric thin-film between metallic electrodes, and an oxide, optionally, conventional SiN.sub.x O.sub.y layer or Si.sub.3 N.sub.4 --SiO.sub.2 bilayer, to protect the substrate from contaminant migration from the ferroelectric layer. Platinum or a metal oxide material (e.g., RuO.sub.2, IrO.sub.2, La.sub.x Sr.sub.1-x CoO.sub.3) may serve as electrodes and provide a lattice matching material for the ferroelectric layer overlying the bottom electrode. Formation of SrBi.sub.2 Ta.sub.2 O.sub.9 or other ferroelectric member of the layered perovskite family may be integrated into conventional CMOS transistor processing.

Growing community of inventors

San Jose, CA, United States of America

Stepan Essaian