Hitachi, Ltd.

Mitsubishi Electric Corporation

Tatsuo Harada

Toshiaki Kita

Shigeo Moriyama

Toshiei Kurosaki

Sumio Hosaka

Akihiro Takanashi

Masaaki Ito

Tsuneo Terasawa

Sho Tanaka

Yoshio Kawamura

Shinji Kuniyoshi

Noritsugu Nomura

Katsumi Nakamura

Hiroyoshi Matsumura

Makoto Okai

Shinji Tsuji

Motohisa Hirao

Akito Nishii

Akio Ohishi

Hidenori Yamaguchi

Katsumi Uryu

Masamoto Akeyama

Hideki Taira

Seiya Hashimoto

Yataro Kondo

An object is to provide a technique that can reduce energy loss during the transient On-period. A semiconductor device includes a first transistor, a second transistor, and a controller. The controller is configured to, before the first transistor enters a transient Off-state, apply a second Off-voltage lower than a first Off-voltage to the second gate, before the first transistor enters a transient On-state, turn On the second transistor, and after the first transistor is turned On, apply the first Off-voltage to the second gate to turn Off the second transistor.

Semiconductor device

According to one aspect, a semiconductor device includes: a buffer layer disposed on a front surface of a second semiconductor layer, and having at least one opening in plan view; and an electrode disposed over the second semiconductor layer and the buffer layer, and being in contact with the second semiconductor layer through the at least one opening, wherein the buffer layer has a higher Vickers hardness than the electrode, and a width w of each of the at least one opening satisfies w&#x3c;W, where s is a thickness of the buffer layer, t is a thickness of the electrode, and W=2&#xd7;(s&#xd7;t&#x2212;s)holds true.

A semiconductor device includes a substrate, a drift layer provided on an upper surface side of the substrate, a base layer provided on the upper surface side of the drift layer, an upper semiconductor layer provided on the upper surface side of the base layer, a first electrode provided on the upper surface of the substrate, a second electrode provided on a rear surface of the substrate, a trench extending to the drift layer from the upper surface of the substrate and a gate electrode provided inside the trench, wherein an inner side surface of the trench has a first surface and a second surface provided below the first surface, the second surface tilts inward of the trench with respect to the first surface, and an intersection point of the first surface and the second surface is provided below the base layer.

Semiconductor device and a manufacturing method of semiconductor device

A semiconductor device includes: a second semiconductor layer in a surface layer of a first semiconductor layer; a third semiconductor layer in a surface layer of the second semiconductor layer; a first trench penetrating the second semiconductor layer and the third semiconductor layer to reach an inside of the first semiconductor layer; a second trench penetrating, from an upper surface of the first semiconductor layer, the third semiconductor layer to reach an inside of the second semiconductor layer; and a fourth semiconductor layer in contact with a bottom of the second trench.

An active cell region, an edge termination region surrounding the active cell region and an intermediate region located at an intermediate position between these regions are provided, the active cell region has a trench gate type MOS structure on a top side, and a vertical structure on a bottom side includes a p-collector layer, an n-buffer layer on the p-collector layer, and an n-drift layer on the n-buffer layer, the n-buffer layer has a first buffer portion provided on the p-collector layer side, and a second buffer portion provided on the n-drift layer side, the peak impurity concentration of the first buffer portion is higher than the peak impurity concentration of the second buffer portion, and the impurity concentration gradient on the n-drift layer side of the second buffer portion is gentler than the impurity concentration gradient on the n-drift layer side of the first buffer portion.

Semiconductor device and method for manufacturing semiconductor device

An n-type buffer regionis arranged between an ndrift regionand a p-type collector region, and has a higher impurity concentration than ndrift regionAssuming that &#x3b1; represents the ratio (WTA/WTB) between WTA expressed as: and the thickness WTB of the drift region held between the base region and the buffer region, the ratio (D/D) of the net dose Dof the collector region with respect to the net dose Dof the buffer region is at least &#x3b1;. Thus, a semiconductor device capable of ensuring a proper margin of SCSOA resistance can be obtained.

An emitter layer is provided in stripes in a direction orthogonal to an effective gate trench region connected to a gate electrode and a dummy trench region isolated from the gate electrode. A width of the emitter layer is determined to satisfy a predetermined relational expression so as not to cause latch-up in an underlying P base layer. In the predetermined relational expression, an upper limit value of the width W of the emitter layer is (3500/Rspb)&#xb7;Wso&#xb7;exp(decimation ratio), where Rspb is a sheet resistance of the P base layer immediately below the emitter layer, Wso is an interval between the trenches, and the decimation ratio is a ratio of the number of the effective gate trench region to the total number of the trench regions. Variations in saturation current in a trench IGBT can be suppressed, and a tolerance of an Reverse Bias Safe Operation Area can be improved.

An n-type first base layer is formed on a semiconductor substratehaving a first major surface and a second major surface, and a p-type second base layer is formed thereon. Between the first base layer and the second base layer, a carrier stored layer is formed. The carrier stored layer has a high-concentration impurity layer and a low concentration impurity layer, and the high-concentration impurity layer has a thickness of 1.5 &#x3bc;m or more and an impurity concentration therethrough is made to be 1.0&#xd7;10cmor more throughout the layer.

Semiconductor device having improved insulated gate bipolar transistor and method for manufacturing the same

A method of fabricating diffraction gratings wherein a photomask is arranged on a substrate which is coated with a photoresist, light is to be incident thereupon at an acute angle relative to the normal direction of the photomask, and a bright/dark pattern is formed on said photoresist by the interference of the transmission light that has passed through the photomask and the diffraction light. The invention further deals with a photomask used for the above method.

Optical device diffraction gratings and a photomask for use in the same

A plane grating, particularly for a monochronomator, is provided with varied-spaced straight and parallel grooves in a light beam path to compensate for other light affecting components, for example a spherical mirror used for collimating or focusing the light beam. The angle of incidence with respect to the light for each of the grooves may vary and the angle of diffraction with respect to the light for each groove may be required to vary with the imperfection of collimation and focusing of the beam. The grooves are varied in their spacing to compensate for the variation of both incidence and diffraction direction.

Monochromator

Monochrometer

A spectrometer is disclosed, in which plural entrance slits are mounted, and a reference light passing through one entrance slit and the light to be measured passing through the other entrance slit are simultaneously focused on a photo-sensitive surface of a detector through a diffraction grating and a focusing optical system, to measure the wavelength of the light to be measured precisely by using the reference light as a standard.

Spectrometer

In a method of producing diffraction gratings by feeding either one of a blank or a groove-ruling tool by an amount consisting of the amount of constant transference and the amount of variable transference that is added thereto, or subtracted therefrom, while reciprocally moving the other one of said blank or said groove-ruling tool, in order to rule grooves of irregular intervals on said blank, a method of producing varied line-space diffraction gratings wherein the region of ruling is divided into a plurality of small regions so that the difference between a maximum value and a minimum value of distance between grooves becomes smaller than a predetermined value, and the amount of constant transference is set to the nearly equal to an average distance between grooves in each of said small regions.

Method of producing varied line-space diffraction gratings

In a concave grating spectrometer for creating a spectral image by dispersing a light to be measured according to the wavelength, an arrangement comprising a concave grating with varied spacing and/or curved grooves formed on a concave spherical surface, and an entrance slit located at such a position on a vertical focal line passing through the center of curvature of the spherical surface, that the sum of the square of the difference between horizontal and vertical focal lengths at each wavelength in the wavelength range takes a minimum value. The light to be measured projected through the entrance slit is dispersed by the concave grating according to the wavelength and an image is focused on the vertical focal line passing through the center of curvature of the spherical grating.

Concave grating spectrometer

There is disclosed a pattern forming apparatus for projecting a pattern which is formed on a reticle upon a photoresist layer on a substrate which comprises an illumination system for illuminating the pattern for forming an optical image, a reduction lenses for reducing the optical pattern image at a certain reduction ratio and projecting the reduced optical pattern image upon the photoresist layer formed on the substrate for exposing the photoresist layer, and liquid sustaining means for filling a gap between at least a portion of the reduction lenses and the photoresist layer with an optically transparent liquid having a refractive index of more than 1 (one).

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Tokyo, Japan

Tatsuo Harada