Abstract: In a p-type clad layer, not only a p-type dopant Zn but also Fe is doped. Its Zn concentration is 1.5×1018 cm?3 and the Fe concentration is 1.8×1017 cm?3. In a semi-insulating burying layer, Fe is doped as an impurity generating a deep acceptor level and the concentration thereof is 6.0×1016 cm?3. The Fe concentration in the p-type clad layer is thus three times higher than the Fe concentration in the burying layer.

Abstract: An optical semiconductor, includes a semiconductor substrate having a (100) principal surface, a waveguide mesa stripe formed on a first region of the semiconductor substrate, the waveguide mesa stripe guiding a light therethrough; a plurality of dummy mesa patterns formed on the semiconductor substrate in a second region at a forward side of the first region, and a semi-insulating buried semiconductor layer formed on the semiconductor substrate so as to cover the first and second regions continuously, the semi-insulating buried semiconductor layer filling a right side and a left side of the waveguide mesa stripe in the first region and a gap between the plurality of dummy mesa patterns in the second region.

Abstract: In a p-type clad layer, not only a p-type dopant Zn but also Fe is doped. Its Zn concentration is 1.5×1018 cm?3 and the Fe concentration is 1.8×1017 cm?3. In a semi-insulating burying layer, Fe is doped as an impurity generating a deep acceptor level and the concentration thereof is 6.0×1016 cm?3. The Fe concentration in the p-type clad layer is thus three times higher than the Fe concentration in the burying layer.

Abstract: An optical semiconductor, includes a semiconductor substrate having a (100) principal surface, a waveguide mesa stripe formed on a first region of the semiconductor substrate, the waveguide mesa stripe guiding a light therethrough; a plurality of dummy mesa patterns formed on the semiconductor substrate in a second region at a forward side of the first region, and a semi-insulating buried semiconductor layer formed on the semiconductor substrate so as to cover the first and second regions continuously, the semi-insulating buried semiconductor layer filling a right side and a left side of the waveguide mesa stripe in the first region and a gap between the plurality of dummy mesa patterns in the second region.

Abstract: An object of the invention is to provide a high-quality soldering method, by reducing, to a vacuum, the pressure in a vacuum room (2) in which a workpiece (10) having solid solder placed thereon consisting solely of tin or including tin and one or more components selected from silver, lead, copper, bismuth, indium and zinc is disposed. A free-radical gas is generated to remove an oxide film on the solder, and, after that, the generation of the free-radical gas is stopped, and the temperature of the solder is raised to a temperature above the melting point of the solder to melt the solder in the non-oxidizing atmosphere.

Abstract: A method of fabricating a semiconductor device includes the steps of forming a step region having a mesa shape in a direction of <011> or <0-11> on a (100) plane of an InP-based compound semiconductor crystal, and burying the step region with InP-based buried layers grown by vapor-phase growth by supplying a base gas to which a chlorinated organic compound is added, the organic chlorine compound including at least two carbon atoms, and each of the carbon atoms is bonded to one chlorine (Cl) atom in one molecule. The chlorinated organic compound is any one of 1,2-dichloroethane, 1,2-dichloropropane, and 1,2-dichloroethylene.

Abstract: A method of fabricating a semiconductor device includes the steps of forming a step region having a mesa shape in a direction of <011> or <0-11> on a (100) plane of an InP-based compound semiconductor crystal, and burying the step region with InP-based buried layers grown by vapor-phase growth by supplying a base gas to which a chlorinated organic compound is added, the organic chlorine compound including at least two carbon atoms, and each of the carbon atoms is bonded to one chlorine (Cl) atom in one molecule. The chlorinated organic compound is any one of 1,2-dichloroethane, 1,2-dichloropropane, and 1,2-dichloroethylene.

Abstract: An optical disc drive according to the present invention can read and write data from/on an optical disc 100 including record tracks to write data thereon and guide tracks for guiding a light beam 40. The drive includes: an optical pickup 101 with a converging optical system to focus the light beam 40 and form a spot thereof on the optical disc 100 for reading or writing the data; a tracking control section for controlling the converging optical system of the optical pickup 101 such that the light beam spot 40 follows a selected track on the optical disc 100 rotating; and a control unit 35 for operating the tracking control section in a first mode or in a second mode. In the first mode, the tracking control section makes the light beam spot 40 follow the recording tracks. In the second mode, the tracking control section makes the light beam spot 40 follow the guide tracks.

Abstract: A soldering method includes exposing a solder paste including a solder powder and a flux on a member to a free radical gas and heating the solder paste to reflow the solder paste and vaporize any active components in the solder paste. Any flux residue is free of active components, so it is not necessary to perform cleaning after soldering to remove flux residue.

Abstract: An optical disc drive according to the present invention can read and write data from/on an optical disc 100 including record tracks to write data thereon and guide tracks for guiding a light beam 40. The drive includes: an optical pickup 101 with a converging optical system to focus the light beam 40 and form a spot thereof on the optical disc 100 for reading or writing the data; a tracking control section for controlling the converging optical system of the optical pickup 101 such that the light beam spot 40 follows a selected track on the optical disc 100 rotating; and a control unit 35 for operating the tracking control section in a first mode or in a second mode. In the first mode, the tracking control section makes the light beam spot 40 follow the recording tracks. In the second mode, the tracking control section makes the light beam spot 40 follow the guide tracks.

Abstract: A soldering method includes exposing a solder paste including a solder powder and a flux on a member to a free radical gas and heating the solder paste to reflow the solder paste and vaporize any active components in the solder paste. Any flux residue is free of active components, so it is not necessary to perform cleaning after soldering to remove flux residue.

Abstract: In track jumping or focus jumping in an optical recording and reproducing apparatus for an optical disk, a light beam is accelerated and decelerated from a track to an adjacent one or from an information plane to an adjacent one in the optical disk. A moving time of light beam under acceleration to an adjacent track or information plane for jumping is measured from the start of acceleration to a predetermined point according to tracking o focus error signal. Then, the deceleration signal for tracking or focus actuator is changed on amplitude or period according to the measured period. Thus, track or focus jumping can be performed stably against external disturbances. Alternatively, the light beam is forced to be driven until the level of the tracking or focus error signal is decreased below a predetermined value after the output of the deceleration signal is completed.

Abstract: A steam supplying apparatus for supplying steam to an ashing process. The apparatus includes a closed water-containing vessel formed from a material having good heat conductive characteristics for evaporating water to provide steam to a vacuum chamber housing an on going ashing process. The closed vessel has a maximum horizontal cross sectional water evaporation area M and a minimum horizontal cross sectional water evaporation area S. The vessel is configured so that M/S<8, and the closed vessel has a submerged inside surface which is coated with a resin. The closed water-containing vessel is provided with a steam outlet connected thereto at a location above the surface of the water therein. The apparatus further includes a temperature-controlled liquid bath for the closed water-containing vessel and the vessel is at least partially submerged in the liquid bath.

Abstract: A method of manufacturing a semiconductor device includes the steps of preparing a semiconductor substrate having a step on a surface thereof and growing a group III-V compound semiconductor layer on a surface of the semiconductor substrate by metal organic vapor phase epitaxy using a source gas added with halogenated hydrocarbon containing one or two halogen atoms per one molecule. The surface of a substrate with a step thereon can be planarized by depositing an embedding layer on a lower level area.

Abstract: A method for controlling an apparatus for supplying steam to an ashing process. The apparatus includes a closed water-containing vessel formed from a material having good heat conductive characteristics for evaporating water to provide steam to a vacuum chamber housing an ongoing ashing process. In accordance with the procedure, steam evaporated in a closed steam supply tank is introduced into a vacuum chamber via a pressure reducing mass-flow controller.

Abstract: A shaping machine wherein either a work or a tool is a rod-like member extending along a straight center line while the other is a member having a hole capable of being fitted on the rod-like member and wherein the work is shaped while the member having the hole passes through the rod-like member from one end toward the other end of the rod-like member. The shaping machine comprises a feed mechanism for causing relative movement of the rod-like member and the member having the hole to each other along the center line of the rod-like member, a center line of the feed mechanism being coincident with the center line of the rod-like member.

Abstract: A method of manufacturing a semiconductor device including the steps of: forming an insulating film on a silicon substrate; forming a resist pattern on the insulating film; etching the insulating film by using the resist pattern as an etching mask to expose a surface of the silicon substrate; and ashing the resist pattern and etching a surface layer at the exposed surface of the silicon substrate at the same time. The ashing/etching step may be performed first at a high temperature at or above 40.degree. C. and then at a lower temperature.

Abstract: A slotting apparatus has a slotting tool for producing a slot of a substantially arcuate cross section axially in an inner circumferential surface of a tubular workpiece held in position. When the slotting tool moves in one direction axially in the tubular workpiece, it follows an arcuate path by moving progressively toward and away from the inner circumferential surface of the tubular workpiece. The slotting tool cuts off the inner circumferential surface of the tubular workpiece, forming an arcuate slot therein. When the slotting tool moves back, it is spaced from the slotted surface region of the workpiece, and travels along a straight path back to its starting position. The slotting tool is supported on a tool support angularly movably supported by first and second link arms in a casing.