Abstract: A semiconductor laser device of the present invention includes a substrate 201 made of n-type GaAs, an active layer 204, and a pair of cladding layers sandwiching the active layer 204. The device further includes a spacer layer 205 adjacent to the active layer 204 and a highly doped saturable absorbing layer 206. The carrier life time is shortened by doping the saturable absorbing layer 206 in a high concentration, whereby stable self-sustained pulsation can be obtained. As a result, a semiconductor laser device can be obtained, which has a low relative noise intensity in a wide range of temperatures.

Abstract: On a substrate of n-type GaAs, an n-type cladding layer of n-type Zn.sub.0.9 Mg.sub.0.1 S.sub.0.13 Se.sub.0.87, an n-type light guiding layer of n-type ZnS.sub.0.06 Se.sub.0.94, an active layer of ZnCdSe and a p-type light guiding layer of p-type ZnS.sub.0.06 Se.sub.0.94 are successively formed. On the p-type light guiding layer, a p-type contact structure is formed. The p-type contact structure includes a first layer of p-type ZnS.sub.0.31 Se.sub.0.54 Te.sub.0.15, a second layer of ZnS.sub.0.47 Se.sub.0.28 Te.sub.0.25, a third layer of p-type ZnS.sub.0.65 Te.sub.0.35, a fourth layer of p-type ZnS.sub.0.5 Te.sub.0.5 and a fifth layer of p-type ZnTe.

Abstract: A semiconductor laser device of the present invention includes a substrate 201 made of n-type GaAs, an active layer 204, and a pair of cladding layers sandwiching the active layer 204. The device further includes a spacer layer 205 adjacent to the active layer 204 and a highly doped saturable absorbing layer 206. The carrier life time is shortened by doping the saturable absorbing layer 206 in a high concentration, whereby stable self-sustained pulsation can be obtained. As a result, a semiconductor laser device can be obtained, which has a low relative noise intensity in a wide range of temperatures.

Abstract: A semiconductor laser device of the present invention includes a substrate 201 made of n-type GaAs, an active layer 204, and a pair of cladding layers sandwiching the active layer 204. The device further includes a spacer layer 205 adjacent to the active layer 204 and a highly doped saturable absorbing layer 206. The carrier life time is shortened by doping the saturable absorbing layer 206 in a high concentration, whereby stable self-sustained pulsation can be obtained. As a result, a semiconductor laser device can be obtained, which has a low relative noise intensity in a wide range of temperatures.

Abstract: Between a semiconductor laser diode and an optical disk, a collimator lens for collimating a laser beam output from the semiconductor laser diode, a liquid crystal optical shutter for attenuating the collimated beam having passed through the collimator lens, and a beam splitter for splitting reflected light from the optical disk are disposed. In addition, a collective lens for collecting the collimated beam obtained by the collimator lens on a data holding surface of the optical disk is further disposed.

Abstract: A semiconductor laser device having an active layer, a pair of cladding layers interposing the active layer and a multi-quantum barrier provided between one of the pair of cladding layers and the active layer is provided, and the multi-quantum barrier includes barrier layers and well layers being alternated with each other. The semiconductor laser device also including an optical guide layer confining light generated in a quantum well layer, and the optical guide layer being undoped.

Abstract: A semiconductor laser according to the present invention includes: a semiconductor substrate; a multilayer structure provided on the semiconductor substrate, the multilayer structure including an active layer, a pair of cladding layers interposing the active layer, and current confining portion for injecting a current into a stripe-shaped predetermined region of the active layer, wherein the current confining portion includes a first current confining layer formed in regions excluding a region corresponding to the predetermined region of the active layer, the first current confining layer having an energy band gap larger than an energy band gap of the active layer and having a refractive index smaller than a refractive index of the active layer.

Abstract: The semiconductor laser of this invention includes an active layer formed in a c-axis direction, wherein the active layer is made of a hexagonal-system compound semiconductor, and anisotropic strain is generated in a c plane of the active layer.

Abstract: An electro-absorption optical modulator, where a waveguide length of the absorption layer is denoted by L, a light confinement coefficient thereof is denoted by .GAMMA., and a performance factor of the absorption layer at an applied voltage V to an absorption layer is denoted by K(V), has design parameters selected so that a relationship .vertline.K(V)-.GAMMA..multidot.L.vertline. .ltoreq.0.005 cm is satisfied in a continuous operation range of a quenching ration T.sub.Att. The waveguide length L is preferably optimizrd so as to satisfy K(V).apprxeq..GAMMA..multidot.L in the operation range.

Abstract: A semiconductor laser includes: an active layer formed of a II-VI group compound semiconductor material; a first cladding layer and a second cladding layer disposed so as to put the active layer therebetween; a light confinement layer provided on the second cladding layer, having an opening for current flow and formed of ZnMgSSe; and a third cladding layer provided at the opening of the light confinement layer. The light confinement layer has high resistivity or has a conductivity type opposite to that of the third cladding layer; the second and third cladding layers are formed of ZnMgSSe; and a Mg content and a S content of the light confinement layer are larger than a Mg content and a S content of the second and third cladding layers.

Abstract: According to one aspect of the invention, a crystal-growing method for forming a II-VI single crystalline semiconductor expressed by Zn.sub.1-x Cd.sub.x Se (where 0<x<0.35) is provided. The crystal-growing method includes a step of epitaxially growing the II-VI single crystalline semiconductor on a substrate by: supplying a II element Zn onto the substrate by using a molecular beam from a ZnSe compound source and a molecular beam from a Zn elemental source; supplying a II element Cd onto the substrate by using a molecular beam from a CdSe compound source; and supplying a VI element Se onto the substrate by using a molecular beam from a ZnSe compound source.

Abstract: A semiconductor laser of the present invention includes: a Zn.sub.1-X Cd.sub.X Se active layer (0<X.ltoreq.0.3); a pair of optical confinement structures for interposing the Zn.sub.1-x Cd.sub.X Se active layer therebetween; and a pair of cladding layers for interposing the optical confinement structures and the Zn.sub.1-X Cd.sub.X Se active layer therebetween, wherein an energy band gap of the optical confinement structure monotonously increases as a distance from the Zn.sub.1-X Cd.sub.X Se active layer increases.

Abstract: A semiconductor device has a capacitive element with excellent leak current characteristics which has a tungsten film with a roughened surface for increasing the surface of a lower electrode. A capacitive element for use in a VLSI memory circuit such as a DRAM or the like is fabricated by forming a thin, roughened tungsten film selectively on a surface of a lower electrode of polysilicon by chemical vapor-phase growth and forming a capacitive insulating film on the surface of the lower electrode of polysilicon, densifying the capacitive insulating film, and forming an upper electrode of a metal element.

Abstract: A semiconductor laser of this invention includes: a semiconductor substrate; a first cladding layer made of first conductivity type ZnMgSSe, which is held by the semiconductor substrate and lattice-matches with the semiconductor substrate; a stripe-shaped second cladding layer made of second conductivity type ZnMgSSe lattice-matching with the semiconductor substrate; a light-emitting layer including a first and a second light guiding layers made of Zn.sub.1-x Mg.sub.x S.sub.1-y Se.sub.y (0.ltoreq.x<1, 0.ltoreq.y<1) and a quantum well layer made of Zn.sub.1-z Cd.sub.z Se (0.ltoreq.z<1) which is interposed between the first and the second light guiding layers, the light-emitting layer being interposed between the first and the second cladding layers; and a burying layer which is made of ZnMgSSe lattice-matching with the semiconductor substrate and formed on sides of the second cladding layer.

Abstract: A semiconductor laser device having an active layer, a pair of cladding layers interposing the active layer and a multi-quantum barrier provided between one of the pair of cladding layers and the active layer is provided. The multi-quantum barrier includes barrier layers and well layers being alternated with each other. Thickness, energy band gap, or impurity concentration of at least one of the barrier layers and well layers in the multi-quantum barrier changes with the distance from the active layer, thereby providing a stable function of reflecting carriers overflowing from the active layer back to the active layer.

Abstract: A semiconductor laser according to the present invention includes: a semiconductor substrate; a multilayer structure provided on the semiconductor substrate, the multilayer structure including an active layer, a pair of cladding layers interposing the active layer, and current confining portion for injecting a current into a stripe-shaped predetermined region of the active layer, wherein the current confining portion includes a first current confining layer formed in regions excluding a region corresponding to the predetermined region of the active layer, the first current confining layer having an energy band gap larger than an energy band gap of the active layer and having a refractive index smaller than a refractive index of the active layer.

Abstract: A stacked capacitor element for a DRAM cell is formed as follows. After a naturally oxidized film on a surface of a polycrystalline silicon film is removed, the polycrystalline silicon film is subjected to a rapid thermal nitriding treatment using lamp annealing so that a capacitor lower electrode of the capacitor element is formed. A tantalum oxide film is deposited on the polycrystalline silicon film and then densified so that a dielectric film of the stacked capacitor element is formed. A conductive film is formed on the tantalum oxide film and patterned. The conductive film is nittided so that a capacitor upper electrode is formed. The capacitor element thus formed enables the suppression of reduction in the capacitance value of the capacitor element of a DRAM and deterioration of the leakage current characteristics.

Abstract: A semiconductor laser device having an active layer, a pair of cladding layers interposing the active layer and a multi-quantum barrier provided between one of the pair of cladding layers and the active layer is provided. The multi-quantum barrier includes barrier layers and well layers being alternated with each other. Thickness, energy band gap, or impurity concentration of at least one of the barrier layers and well layers in the multi-quantum barrier changes with the distance from the active layer, thereby providing a stable function of reflecting carriers overflowing from the active layer back to the active layer.

Abstract: In a conventional method for forming a capacity element for DRAM, a tantalum oxide film is formed on the surface of polycrystal silicon film constituting a capacity lower electrode, and a high temperature treatment is then carried out in an oxygen atmosphere to improve leakage current properties, thereby converting this tantalum oxide film. In the capacity element having the thus formed capacity insulating film, an obtainable capacity value is small. In the present invention, a densification treatment is carried out at a relatively low temperature in place of the high temperature treatment step of the tantalum oxide film, whereby the capacity element having the large capacity value can be formed without deteriorating the leakage current properties.

Abstract: A capacitor element of a semiconductor device used for a super-LSI is formed by the steps including (a) removing a natural oxide film on a surface of a lower electrode of polysilicon, (b) forming on the surface of the lower electrode an impurity-doped tantalum oxide film, and (c) forming an upper electrode with at least a bottom thereof constituted by titanium nitride. The steps may further include (d) nitriding the surface of the lower electrode after the removal of the natural oxide film, and (e) densifying the tantalum oxide film by way of a high temperature heat treatment after the formation of the tantalum oxide film. In this way, it is possible to reduce thickness of a capacitive insulating film and to form the capacitor element in which the leakage current characteristics are improved.