Sumitomo Electric Industries, Limited

Kyocera Document Solutions Inc.

Other

Kosuke Uchida

Toru Hiyoshi

Takeyoshi Masuda

Keiji Wada

Yu Saitoh

Takashi Tsuno

Kazuya Yamashita

Mitsuhiko Sakai

Masaki Furumai

Noriaki Sumikura

Taro Nishiguchi

Shingo Yoshida

Taku Horii

Yasuhiro Tauchi

Mitsuhiro Goda

Hiroshi Inui

Hideji Mizutani

Takayuki Kurihara

A first main surface of a silicon carbide substrate is provided with a first trench and a second trench. The first trench is defined by a first side surface and a first bottom surface. The second trench is defined by a second side surface and a second bottom surface. The silicon carbide substrate includes a first impurity region, a second impurity region, a third impurity region, and a fourth impurity region. A first insulating film is in contact with each of the first side surface and the first bottom surface. A gate electrode is provided on the first insulating film. A second insulating film is in contact with each of the second side surface and the second bottom surface. The second impurity region has a connection region electrically connected to the fourth impurity region and extending toward the fourth impurity region along the second side surface.

Silicon carbide semiconductor device

A silicon carbide substrate has a first main surface and a second main surface opposite to the first main surface. A gate pad faces the first main surface. A drain electrode is in contact with the second main surface. The silicon carbide substrate includes a first impurity region constituting the second main surface and having a first conductivity type, a second impurity region provided on the first impurity region and having a second conductivity type different from the first conductivity type, a third impurity region provided on the second impurity region and having the first conductivity type, and a fourth impurity region provided on the third impurity region, constituting the first main surface, and having the second conductivity type. Each of the first impurity region, the second impurity region, the third impurity region, and the fourth impurity region is located between the gate pad and the drain electrode.

A silicon carbide substrate has at least one of a first structure and a second structure. The first structure is such that a first impurity region is in contact with a second impurity region, a third impurity region is separated from a fourth impurity region by a second drift region, and the second impurity region has a width greater than a width of the fourth impurity region in a direction parallel to a first main surface. The second structure is such that the first impurity region is separated from the second impurity region by a first drift region, the third impurity region is in contact with the fourth impurity region, and the fourth impurity region has a width greater than a width of the second impurity region in the direction parallel to the first main surface.

The side surface has a first outer end surface. The bottom surface has a first bottom portion continuous to the first outer end surface, and a second bottom portion continuous to the first bottom portion and located on a side opposite to the inner end surface with respect to the first bottom portion. A silicon carbide substrate has a first region and a second region located between the at least one gate trench and a second main surface, and spaced from each other with a drift region being sandwiched therebetween. In a direction parallel to the first outer end surface, a spacing between the first region and the second region located between the first bottom portion and the second main surface is smaller than a spacing between the first region and the second region located between the second bottom portion and the second main surface.

A silicon carbide semiconductor device includes a silicon carbide substrate and a gate insulating film. The silicon carbide substrate has a first main surface and a second main surface opposite to the first main surface. The gate insulating film is provided on the first main surface. The silicon carbide substrate includes a first body region having p type, a second body region having p type, and a JFET region provided between the first body region and the second body region and having n type. The JFET region has both a first impurity capable of providing the p type and a second impurity capable of providing the n type. A concentration of the second impurity is higher than a concentration of the first impurity. The silicon carbide semiconductor device capable of suppressing dielectric breakdown of the gate insulating film is provided.

A silicon carbide semiconductor device includes a gate insulating film and a gate electrode. A first main surface is provided with a trench defined by a side surface penetrating a third impurity region and a second impurity region to reach a first impurity region, and a bottom provided continuously with the side surface. In a stress test in which a gate voltage of at least one of &#x2212;10 V and 20 V is applied to the gate electrode for 100 hours at a temperature of 175&#xb0; C., where a threshold voltage before the stress test is defined as a first threshold voltage and a threshold voltage after the stress test is defined as a second threshold voltage, an absolute value of a difference between the first threshold voltage and the second threshold voltage is not more than 0.25 V. The second threshold voltage is not less than 2.5 V.

An image forming apparatus () includes a frame () supporting an attached object () inserted into an apparatus body () and an attachment device () fixing the attached object () supported by the frame (). The frame () includes a leading end plate () facing to a leading end in an inserting direction of the attached object (). The attached object () includes a fixing pin () supported by the leading end plate () in advanceable/retreatable state along the inserting direction and formed connectable to the attached object (), a biasing member () biasing the fixing pin () toward the inserting direction and a locking member () restricting dropout of the fixing pin (). The attachment device () holds the attached object () being connected to the fixing pin () and receiving the biasing force of the biasing member () at a position gravitated to the leading end plate ().

Image forming apparatus

An optical scanning device () includes cleaning holders (), light transmitting members (), a linear member (), a winding motor (), and stoppers (). The two cleaning holders () are coupled to the linear member (). The linear memberis driven to circulate by the winding motor (), whereby the two cleaning holders () move and each cleaning member slides on a corresponding one of the light transmitting members (). When the cleaning holders () come into contact with the respective stoppers (), the stoppers () restrict movement of the respective cleaning holders () in one of directions of extension of the light transmitting members (). A contact determining section () determines, based on a current value of the winding motor (), that the cleaning holder () has come into contact with the stopper ().

A trench has first to third side surfaces respectively constituted of first to third semiconductor layers. A first side wall portion included in a first insulating film has first to third regions respectively located on the first to third side surfaces. A second insulating film has a second side wall portion located on the first side wall portion. The second side wall portion has one end and the other end, the one end being connected to the second bottom portion of the second insulating film, the other end being located on one of the first and second regions, the other end being separated from the third region.

Silicon carbide semiconductor device and method for manufacturing same

A silicon carbide epitaxial layer includes: a first impurity region; a second impurity region; and a third impurity region. A gate insulating film is in contact with the first impurity region, the second impurity region, and the third impurity region. A groove portion is formed in a surface of the first impurity region, the surface being in contact with the gate insulating film, the groove portion extending in one direction along the surface, a width of the groove portion in the one direction being twice or more as large as a width of the groove portion in a direction perpendicular to the one direction, a maximum depth of the groove portion from the surface being not more than 10 nm.

An optical scanning device includes a scanning member, a plurality of light sources, a first reflection mirror, and a second reflection mirror. The scanning member scans incident laser beams in a predetermined main scanning direction. The plurality of light sources emit the laser beams from positions that are different along a sub scanning direction that is perpendicular to an optical axis direction of the laser beams and the main scanning direction. The first reflection mirror is inclined around the main scanning direction as a rotation axis, is inclined around the sub scanning direction as another rotation axis, and reflects the laser beams emitted from the light sources. The second reflection mirror is inclined around the main scanning direction as a rotation axis, is inclined around the sub scanning direction as another rotation axis, and reflects the laser beams reflected by the first reflection mirror toward the scanning member.

Optical scanning device, image forming apparatus, aperture fixing method

A method for manufacturing a silicon carbide semiconductor device includes the following steps. A silicon carbide substrate is prepared. A first heating step of heating the silicon carbide substrate in an atmosphere of oxygen is performed. A second heating step of heating the silicon carbide substrate to a temperature of 1300&#xb0; C. or more and 1500&#xb0; C. or less in an atmosphere of gas containing nitrogen atoms or phosphorus atoms is performed after the first heating step. A third heating step of heating the silicon carbide substrate in an atmosphere of a first inert gas is performed after the second heating step. Thus, the silicon carbide semiconductor device in which threshold voltage variation is small, and a method for manufacturing the same can be provided.

A developing device according to the present disclosure includes a developer container, a duct, a duct coupling portion and a handle portion, and is removable with respect to an image forming apparatus. The duct is formed in the developer container and sucks floating toner together with air within the developer container. The duct coupling portion is formed at an end of the duct and is coupled to a toner suction portion of the image forming apparatus. The handle portion is formed in the shape of a flat plate and is formed to protrude from immediately below the duct coupling portion in a horizontal direction. A hollow portion is formed within the handle portion. A through hole is formed in a portion of an upper surface of the handle portion that is protruded as compared with an opening surface of the duct coupling portion and communicates with the hollow portion.

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Osaka, Japan

Kosuke Uchida