Patents by Inventor Takao Takenaka
Takao Takenaka has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 8728870Abstract: Provided are a thin film silicon wafer having high gettering capability, a manufacturing method therefor, a multi-layered silicon wafer formed by laminating the thin film silicon wafers, and a manufacturing method therefor. The thin film silicon wafer is manufactured by: forming one or more gettering layers immediately below a device layer which is formed in a vicinity of a front surface of a semiconductor silicon wafer; fabricating a device in the device layer of the semiconductor silicon wafer; and after the device has been fabricated, removing part of the semiconductor silicon wafer from a rear surface thereof to immediately below the gettering layers so as to leave at least one of the gettering layers in place. As a result, the thin film silicon wafer is allowed to have gettering capability even after having been reduced in thickness to be in a thin film form.Type: GrantFiled: June 4, 2008Date of Patent: May 20, 2014Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Satoshi Tobe, Takao Takenaka
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Publication number: 20100171195Abstract: Provided are a thin film silicon wafer having high gettering capability, a manufacturing method therefor, a multi-layered silicon wafer formed by laminating the thin film silicon wafers, and a manufacturing method therefor. The thin film silicon wafer is manufactured by: forming one or more gettering layers immediately below a device layer which is formed in a vicinity of a front surface of a semiconductor silicon wafer; fabricating a device in the device layer of the semiconductor silicon wafer; and after the device has been fabricated, removing part of the semiconductor silicon wafer from a rear surface thereof to immediately below the gettering layers so as to leave at least one of the gettering layers in place. As a result, the thin film silicon wafer is allowed to have gettering capability even after having been reduced in thickness to be in a thin film form.Type: ApplicationFiled: June 4, 2008Publication date: July 8, 2010Applicant: SHIN-ETSU HANDOTAI CO., LTDInventors: Satoshi Tobe, Takao Takenaka
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Patent number: 5739553Abstract: The present invention provides an AlGaInP light-emitting device with a longer life and higher reliability. The AlGaInP light-emitting device comprises an n-type (Al.sub.0.7 Ga.sub.0.3).sub.0.51 In.sub.0.49 P cladding layer (about 1 .mu.m in thickness), an (Al.sub.0.15 Ga.sub.0.85).sub.0.51 In.sub.0.49 P active layer (about 0.6 .mu.m in thickness), a p-type (Al.sub.0.7 Ga.sub.0.3).sub.0.51 In.sub.0.49 P cladding layer (about 1 .mu.m in thickness), and a p-type current-spreading layer composed of either a p-type Al.sub.0.7 Ga.sub.0.3 As layer (about 3 .mu.m in thickness) or a p-type Al.sub.0.7 Ga.sub.0.3 As.sub.0.97 P.sub.0.03 layer (about 3 .mu.m in thickness) and a p-type GaAs.sub.0.5 P.sub.0.5 layer (about 7 .mu.m in thickness), in sequence formed on an n-type GaAs substrate, and further an upper surface electrode mounted on the p-type GaAs.sub.0.5 P.sub.0.5 layer and a lower surface electrode mounted on the lower surface of the n-type GaAs substrate.Type: GrantFiled: December 26, 1995Date of Patent: April 14, 1998Assignee: Shin-Etsu Handotai, Co., Ltd.Inventors: Nobuhiko Noto, Keizo Adomi, Takao Takenaka
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Patent number: 5612539Abstract: A lifetime related quality evaluation method, used with a semiconductor wafer having a semiconductor thin layer over the main surface of a semiconductor substrate, for evaluating the lifetime related quality of the semiconductor thin layer and/or the vicinity thereof, characterized by: generating electron-hole pairs in the vicinity of a surface of the semiconductor thin layer by the use of excitation light having a larger energy than the band gap of a semiconductor to be tested; then detecting the intensity at a particular wavelength of light emitted by recombination of the electron-hole pairs; and evaluating the lifetime related quality of the semiconductor thin layer and/or the vicinity thereof based on the detected intensity. The lifetime related quality evaluation method realizes a non-contact, non-destructive quality evaluation of the epitaxial semiconductor wafer.Type: GrantFiled: November 14, 1995Date of Patent: March 18, 1997Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Ryoji Hoshi, Yutaka Kitagawara, Takao Takenaka
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Patent number: 5600158Abstract: A semiconductor light emitting device comprising an n-type GaAs substrate, a light emitting layer portion consisting of an AlGaInP double heterojunction structure formed on the substrate, and a p-type current spreading layer formed on the light emitting layer portion, wherein the p-type current spreading layer comprises an undoped current spreading layer and a heavily-doped current spreading layer formed on said undoped current spreading layer. With this construction, it is possible to achieve a stable control of carrier concentration in a p-type cladding layer, to prevent deterioration of the interface between the p-type cladding layer and an active layer and also to prevent crystallinty-deterioration of the active layer with the result that the emission intensity of the device can be increased to a considerable extent.Type: GrantFiled: August 14, 1995Date of Patent: February 4, 1997Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Nobuhiko Noto, Keizo Adomi, Takao Takenaka
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Patent number: 5598452Abstract: According to the invention, it is sought to provide a method of evaluating single crystal of silicon, which permits determination of the amount of precipitated oxygen of even a sample having been heat treated and with unknown initial interstitial oxygen concentration. X-rays radiated from X-ray source 7 is converted by slit 6 into a thin, parallel incident X-ray beam 3 to be incident on sample single crystal 1. After adjusting the angle .theta.1 of sample with respect to the incident X-ray beam such as to satisfy Bragg conditions, diffracted X-rays 4 produced by diffraction on the sample single crystal 1 are coupled from the back side thereof through X-ray receiving slit 8 to scintillator 5 for intensity measurement. The amount of precipitated oxygen is calculated from the measured diffracted X-ray intensity.Type: GrantFiled: September 6, 1995Date of Patent: January 28, 1997Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Hiroshi Takeno, Ryoji Hoshi, Satoshi Ushio, Takao Takenaka
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Patent number: 5597761Abstract: An epitaxial layer(s) of compound semiconductor alloy doped with nitrogen and represented by the formula (Al.sub.x Ga.sub.1-x).sub.y In.sub.1-y P (0<x.ltoreq.1, 0<y.ltoreq.1) is formed on a compound semiconductor single crystal substrate composed of an element(s) from Group III and an element(s) from Group V in the periodic table by means of the metalorganic vapor phase epitaxy method (MOVPE method), while controlling the amount of the organic aluminum compound introduced. The organic aluminum compound is, for example, trimethyl aluminum (TMAl). The nitrogen-doped epitaxial layer is, for example, an active layer composed of said compound semiconductor alloy which has a band gap of 2.30 eV or larger and also has an alloy composition of an indirect transition area or similar to it.Type: GrantFiled: March 10, 1995Date of Patent: January 28, 1997Assignee: Shin-Etsu Handotai Co LtdInventors: Keizo Adomi, Nobuhiko Noto, Akio Nakamura, Takao Takenaka
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Patent number: 5585305Abstract: A method for fabricating a semiconductor device includes the steps of growing a second semiconductor layer on a first semiconductor layer which is highly doped with an impurity such as Zn and diffusing the impurity concurrently with the growing step of the second semiconductor layer from the first semiconductor layer as an impurity source to the second semiconductor layer to have a predetermined carrier concentration profile, by controlling both the diffusing speed of said impurity and the growing speed of said second semiconductor layer by changing the temperature in accordance with a predetermined sequence to have a predetermined carrier concentration profile in the second semiconductor layer.Type: GrantFiled: May 26, 1994Date of Patent: December 17, 1996Assignee: Shin-Etsu Handotai Co. Ltd.Inventors: Masato Yamada, Takao Takenaka
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Patent number: 5533387Abstract: The height x.sub.i (i=1, 2, . . . , N) of a plurality of measuring points on a silicon wafer from a reference plane is measured by means of an AFM (atomic force microscope), the autocorrelation function R.sub.j represented by the equation below is determined: ##EQU1## Where x denotes: ##EQU2## is determined, an arbitrary number of autocorrelation function R.sub.j with large value from said autocorrelation function R.sub.j are selected, and the microroughness on said silicon wafer is analyzed based on the distances between the point R.sub.j=0 and said selected points R.sub.j 's with large value except for R.sub.j=0.Type: GrantFiled: September 14, 1995Date of Patent: July 9, 1996Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Ken Aihara, Yutaka Kitagawara, Takao Takenaka
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Patent number: 5444269Abstract: An AlGaInP double heterojunction structure or an AlGaInP single heterojunction structure is formed on a first conductivity-type GaAs substrate, and then a layer made of a second conductivity-type Al.sub.w Ga.sub.1-w As.sub.1-v P.sub.v mixed crystal (Al.sub.0.7 Ga.sub.0.3 As.sub.0.97 P.sub.0.03, for example) which has the bandgap energy larger than the energy of photon emitted from the active layer of said light emitting layer portion, and has good lattice-matching with (Al.sub.B Ga.sub.1-B).sub.0.51 In.sub.0.49 P mixed crystal (layer) constituting said light emitting layer portion, is formed as a current spreading layer on top of said light emitting layer portion. Here, w and v are in the range of 0.45.ltoreq.w<1 and 0<v.ltoreq.0.08, respectively.Type: GrantFiled: May 31, 1994Date of Patent: August 22, 1995Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Keizo Adomi, Nobuhiko Noto, Takao Takenaka
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Patent number: 5442203Abstract: A semiconductor light emitting device has a light emitting layer portion comprising AlGaInP layers formed on a GaAs substrate. A light reflecting layer portion comprising alternately laminated layers with different refractive indices is provided between the GaAs substrate and the light emitting layer portion. The light reflecting layer portion comprises Al.sub.w Ga.sub.1-w As.sub.1-v P.sub.v layers (where: 0.ltoreq.w.ltoreq.1, 0<v.ltoreq.0.05 w). An active layer which constitutes the light emitting layer portion comprises an (Al.sub.y Ga.sub.1-y).sub.0.51 In.sub.0.49 P layer (where: 0.ltoreq.y.ltoreq.0.7).Type: GrantFiled: August 18, 1994Date of Patent: August 15, 1995Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Keizo Adomi, Nobuhiko Noto, Takao Takenaka
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Patent number: 5442201Abstract: An epitaxial layer(s) of compound semiconductor alloy doped with nitrogen and represented by the formula (Al.sub.x Ga.sub.1-x).sub.y In.sub.1-y P (0<x.ltoreq.1, 0<y.ltoreq.1) is formed on a compound semiconductor single crystal substrate composed of an element(s) from Group III and an element(s) from Group V in the periodic table by means of the metalorganic vapor phase epitaxy method (MOVPE method), while controlling the amount of the organic aluminum compound introduced. The organic aluminum compound is, for example, trimethyl aluminum (TMAl). The nitrogen-doped epitaxial layer is, for example, an active layer composed of said compound semiconductor alloy which has a band gap of 2.30 eV or larger and also has an alloy composition of an indirect transition area or similar to it.Type: GrantFiled: March 23, 1994Date of Patent: August 15, 1995Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Keizo Adomi, Nobuhiko Noto, Akio Nakamura, Takao Takenaka
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Patent number: 5401684Abstract: Disclosed are a light-emitting semiconductor device substrate and a method of manufacturing the same. The substrate is prepared by causing a Ga.sub.1-x Al.sub.x As compound semiconductor single crystalline thick-film layer having a first AlAs mole fraction and a low Al containing and oxidation-delaying Ga.sub.1-y Al.sub.y As compound semiconductor single crystalline thin film serving as a surface protective layer and having a second AlAs mole fraction to be sequentially grown on a GaAs crystal substrate. The method comprises the step of causing the thick-film layer and the thin film to be sequentially grown on the GaAs crystal substrate. The GaAs crystal substrate is removed after sequential epitaxial growth of the thick-film layer and thin film on the GaAs crystal substrate.Type: GrantFiled: December 2, 1992Date of Patent: March 28, 1995Assignee: Shin-Etsu Handatai Co., Ltd.Inventors: Masato Yamada, Takao Takenaka, Shinji Orimo
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Patent number: 5386118Abstract: A method and apparatus disclosed by this invention allows determination of the interstitial oxygen concentration in a silicon single crystal to be effected stably and accurately without being appreciably affected by change of the temperature of a sample under test. The interstitial oxygen concentration in the silicon single crystal is determined on the basis of the value of:(Light absorption coefficient).times.[1+a.times.(peak half width)]or the value of:(Light absorption coefficient).times.[1+b.times.(peak area)/ (peak height)](wherein a or b stands for a parameter whose value depends on the conditions for determination or the apparatus for determination and should be empirically fixed with respect to specific conditions of determination or the apparatus used therefor) concerning an interstitial oxygen absorption peak at 1106 cm.sup.-1 obtained by means of an infrared spectrophotometer.Type: GrantFiled: March 29, 1993Date of Patent: January 31, 1995Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Yutaka Kitagawara, Hiroshi Kubota, Masaro Tamatsuka, Takao Takenaka, Kazuhisa Takamizawa
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Patent number: 5366552Abstract: A method and an apparatus capable of efficiently producing an epitaxial layer grown at one time on a multiplicity of substrates with uniform thickness and quality are disclosed, in which a sealable growth chamber filled in a solution used to achieve liquid-phase epitaxial growth and holding therein at least one row of thin plate-like substrate is turned about the horizontal axis. The growth chamber is tilted or overturned so that the solution in the growth chamber is stirred homogeneously and the effect of gravity on the solution is excluded. A solution chamber for holding therein the solution is connected with the growth chamber via a gate valve. After the liquid-phase epitaxial growth, the growth chamber is overturned and then the gate valve is opened so that the solution in the growth chamber returns to the solution chamber. Thus, reuse of the solution is possible.Type: GrantFiled: June 11, 1992Date of Patent: November 22, 1994Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Masato Yamada, Takao Takenaka, Masahisa Endo
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Patent number: 5362683Abstract: To manufacture epitaxial wafers with a smaller amount of semiconductor crystals at a lower cost by means of an efficient epitaxial growth process. An epitaxial wafer is made by forming, by means of epitaxial growth, GaAlAs layers with identical structures on both sides of a GaAs substrate wafer with the crystal plane orientation of {100}. The epitaxial wafer is then divided in the GaAs substrate wafer portion into two pieces to obtain two epitaxial wafers. To perform the epitaxial growth process, a plurality of GaAs substrate wafers are held at their edges and then the GaAs substrate wafers are placed in a Ga solution at prescribed spatial intervals. To divide the epitaxial wafer in the GaAs substrate portion into two pieces, the substrate wafer portion is cut parallel to the main surface. Or, the GaAs substrate wafer can also be removed by means of etching while the epitaxial wafer is rotated at a high speed in the etching solution.Type: GrantFiled: March 4, 1994Date of Patent: November 8, 1994Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Takao Takenaka, Masahisa Endo, Masato Yamada
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Patent number: 5323027Abstract: In a light emitting device comprising a first clad layer composed of a mixed crystal compound semiconductor of first type conductivity, an active layer composed of a mixed crystal compound semiconductor of first type conductivity which has the mixed crystal ratio required to emit the prescribed wavelength, and a second clad layer composed of a mixed crystal compound semiconductor of second type conductivity which has a mixed crystal ratio equivalent to that of the first clad layer, the active layer is sandwiched by the first and second clad layers and forms the double hetero structure with the first and second clad layers, and the carrier concentration in the first clad layer near the junction with the active layer was made to be 5.times.10.sup.16 cm.sup.-3 or less. The carrier concentration in the active layer is preferably 1.times.10.sup.17 cm.sup.-3 or less, and the carrier concentration in the second clad layer is preferably 5.times.10.sup.16 cm.sup.-3 or more.Type: GrantFiled: May 29, 1992Date of Patent: June 21, 1994Assignee: Shin-Etsu Handotai Kabushiki KaishaInventors: Masato Yamada, Takao Takenaka
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Patent number: 5302832Abstract: Spatial distribution of deep level concentration near the surface of a semiconductor wafer is evaluated quickly and accurately by a method which comprises at least a step of scanning the surface of the semiconductor wafer in the X and Y direction with a laser beam for carrier excitation from a laster beam source in accordance with the room-temperature photoluminescence (PL) process thereby measuring the wafer map (M.sub.D) of deep level PL intensity (I.sub.D) and wafer map (M.sub.B) of band edge PL intensity (I.sub.B) in the semiconductor wafer and a step of dividing the wafer map (M.sub.D) of PL intensity (I.sub.D) by the .nu.'th power of the wafer map (M.sub.B) of PL intensity (I.sub.B) {the magnitude of the .nu.'th power presenting the numerical value obtained by empirically confirming the dependence of the band edge PL intensity (I.sub.B) on the power of the excitation laster mean} thereby determining the spatial distribution (M.sub.N) of the relative value of deep level concentration (N.sub.Type: GrantFiled: September 25, 1992Date of Patent: April 12, 1994Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Yutaka Kitagawara, Ryoji Hoshi, Takao Takenaka
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Patent number: 5254172Abstract: An semiconductor substrate processing apparatus of the type including a furnace tube associated with a fluid supply unit and a fluid discharge unit, wherein the furnace tube is rotatably supported by pairs of confronting rollers and rotated by a motor under the control of a controller in order to achieve various kinds of processing of semiconductor substrates within the furnace tube. With this rotatable furnace tube, the apparatus exhibits high radial temperature uniformity and is able to prevent deformation of the furnace tube.Type: GrantFiled: March 19, 1992Date of Patent: October 19, 1993Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Toshio Otaki, Hitoshi Ikeda, Masato Yamada, Takao Takenaka
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Patent number: 5228927Abstract: A heat-treating method for an indium-doped dislocation-free gallium arsenide monocrystal having a low carbon concentration and grown in the Liquid Encapsulated Czochralski method, comprising a two-step heat treatment:(i) heating the monocrystal at a temperature between 1050.degree. C. and 1200.degree. C. for a predetermined time length, and cooling the monocrystal quickly; and(ii) heating the monocrystal at a temperature between 750.degree. C. and 950.degree. C. for a predetermined time length, and cooling the monocrystal quickly.Type: GrantFiled: March 29, 1991Date of Patent: July 20, 1993Assignee: Shin-Etsu Handotai Company LimitedInventors: Yutaka Kitagawara, Susumu Kuwahara, Takao Takenaka