Abstract: 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 ?10 V and 20 V is applied to the gate electrode for 100 hours at a temperature of 175° 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.

Abstract: 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.

Abstract: An optical scanning device (12) includes cleaning holders (511, 512), light transmitting members (52), a linear member (54), a winding motor (55), and stoppers (56a, 56b). The two cleaning holders (511, 512) are coupled to the linear member (54). The linear member 54 is driven to circulate by the winding motor (55), whereby the two cleaning holders (511, 512) move and each cleaning member slides on a corresponding one of the light transmitting members (52). When the cleaning holders (511, 512) come into contact with the respective stoppers (56a, 56b), the stoppers (56a, 56b) restrict movement of the respective cleaning holders (511, 512) in one of directions of extension of the light transmitting members (52). A contact determining section (913) determines, based on a current value of the winding motor (55), that the cleaning holder (511, 512) has come into contact with the stopper (56a, 56h).

Abstract: An image forming apparatus (1) includes a frame (61) supporting an attached object (23) inserted into an apparatus body (2) and an attachment device (62) fixing the attached object (23) supported by the frame (61). The frame (61) includes a leading end plate (61b) facing to a leading end in an inserting direction of the attached object (23). The attached object (23) includes a fixing pin (65) supported by the leading end plate (61b) in advanceable/retreatable state along the inserting direction and formed connectable to the attached object (23), a biasing member (66) biasing the fixing pin (65) toward the inserting direction and a locking member (67) restricting dropout of the fixing pin (65). The attachment device (62) holds the attached object (23) being connected to the fixing pin (65) and receiving the biasing force of the biasing member (67) at a position gravitated to the leading end plate (61b).

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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° C. or more and 1500° 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: There is provided a silicon carbide semiconductor device having an improved switching characteristic. A MOSFET includes a silicon carbide layer, a gate insulating film, a gate electrode, and a source electrode. The silicon carbide layer includes a drift region, a body region, and a contact region. The source electrode is in contact with the contact region in a main surface. The MOSFET is configured such that contact resistance of the source electrode with respect to the contact region is not less than 1×10?4 ?cm2 and not more than 1×10?1 ?cm2. Moreover, when viewed in a plan view of the main surface, an area of the contact region is not less than 10% of an area of the body region.

Abstract: 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° C. or more and 1500° 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.

Abstract: n 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.

Abstract: 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° C. or more and 1500° 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.

Abstract: A silicon carbide semiconductor device includes a silicon carbide layer, an element region including a semiconductor element portion formed in the silicon carbide layer, a JTE region (first electric field relaxing region), an insulating film disposed on a first main surface and covering the JTE region, and a pad electrode electrically connected to the JTE region. The pad electrode includes an extension portion extending from an end of the JTE region close to the element region in a peripheral direction from the element region toward the JTE region, the extension portion being disposed on the insulating film. The extension portion overlies at least a portion of the JTE region.

Abstract: An optical scanning device includes two cleaning holders. The two cleaning holders each include two cleaning members. The two cleaning holders are connected to a wire-shaped member. In accompaniment of circulation of the wire-shaped member, the two cleaning holders travel to cause the cleaning members to slide on corresponding transmissive members. Upon one of the two cleaning holders coming into contact with a first stopper at one end of its travel path, a circulating direction of the wire-shaped member is reversed. Upon the other of the two cleaning holders coming into contact with a second stopper at one end of its travel path, the wire-shaped member stops circulating.

Abstract: A light scanning device includes a housing, a plurality of permeable members, a plurality of cleaning members, a plurality of cleaning holders, a linear member, and a driving unit. The plurality of permeable members close the respective plurality of the emission ports. The plurality of cleaning holders extend over the plurality of the permeable members adjacent to one another. The plurality of the cleaning holders each have a holding unit that holds at least the two cleaning members. The linear member is connected to the plurality of the cleaning holders. The driving unit causes the linear member to run circularly. The cleaning members each slide on the corresponding permeable member in association with the linear member running circularly. The cleaning holders each connected to the linear member at a center of the holding unit in an extending direction of the holding unit.

Abstract: There is provided a silicon carbide semiconductor device allowing for suppression of breakage of an element upon short circuit of load. A MOSFET includes a silicon carbide layer, a gate insulating film, a gate electrode, a source electrode, and a drain electrode. The silicon carbide layer includes a drift region, a body region, and a source region. The MOSFET is configured such that a relational expression of n<?0.02RonA+0.7 is established in a case where a contact width of the source region and the source electrode is represented by n (?m) in a cross section in a thickness direction of the silicon carbide layer and a migration direction of carriers in the body region and where on resistance of the MOSFET in a state in which an inversion layer is formed in a channel region is represented by RonA (m?cm2).