Abstract: In forming an ohmic electrode on a back surface of an n-type SiC substrate, an n+-type semiconductor region is formed in a surface layer of the back surface of an n-type epitaxial substrate by ion implantation. In this ion implantation, the impurity concentration of the n+-type semiconductor region is a predetermined range and preferably a predetermined value or less, and an n-type impurity is implanted by acceleration energy of a predetermined range such that the n+-type semiconductor region has a predetermined thickness or less. Thereafter, a nickel layer and a titanium layer are sequentially formed on the surface of the n+-type semiconductor region, the nickel layer is heat treated to form a silicide, and the ohmic electrode formed from nickel silicide is formed. In this manner, a back surface electrode that has favorable properties can be formed while peeling of the back surface electrode can be suppressed.

Abstract: In some aspects of the invention, a layer containing titanium and nickel is formed on an SiC substrate. A nickel silicide layer containing titanium carbide can be formed by heating. A carbon layer precipitated is removed by reverse sputtering. Thus, separation of an electrode of a metal layer formed on nickel silicide in a subsequent step is suppressed. The effect of preventing the separation can be further improved when the relation between the amount of precipitated carbon and the amount of carbon in titanium carbide in the surface of nickel silicide from which the carbon layer has not yet been removed satisfies a predetermined condition.

Abstract: A method of manufacturing a silicon carbide semiconductor device includes grinding a back surface of a semiconductor substrate formed of silicon carbide to reduce thickness thereof and provide an altered layer that is ground; removing by polishing or etching, the altered layer from the back surface; forming a nickel film on the back surface of the semiconductor substrate after removing the altered layer; heat treating the nickel film to forming a nickel silicide layer by silicidation; and forming a metal electrode on a surface of the nickel silicide layer.

Abstract: A titanium layer and a nickel layer are sequentially formed on a back surface of a SiC wafer. Next, by high-temperature heat treatment, the SiC wafer is heated and the titanium layer and the nickel layer are sintered forming a nickel silicide layer that includes titanium carbide. By this high-temperature heat treatment, an ohmic contact of the SiC wafer and the nickel silicide layer is formed. Thereafter, on the nickel silicide layer, a back surface electrode multilayered structure is formed by sequentially stacking a titanium layer, a nickel layer, and a gold layer. Here, in forming the nickel layer that configures a back surface electrode multilayered structure, the nickel layer is formed under a condition that satisfies 0.0<y?0.0013x+2.0, where the thickness of the nickel layer is x [nm] and the deposition rate of the nickel layer is y [nm/second]. Thus, peeling of the back surface electrode can be suppressed.

Abstract: A surface of a silicon carbide substrate on which a graphite layer is formed is covered with a metal layer which can form carbide. Then, the silicon carbide substrate is annealed to cause reaction between a metal in the metal layer which can form carbide and carbon in the graphite layer so as to change the graphite layer between the metal layer which can form carbide and the silicon carbide substrate to a metal carbide layer. Thus, the graphite layer is removed. The adhesion between the metal layer which can form carbide and the silicon carbide substrate can be improved so that separation of the metal layer which can form carbide can be suppressed. Graphite deposits can be suppressed due to the removal of the graphite layer so that separation of a wiring metal film formed on a surface of the metal layer which can form carbide can be suppressed.

Abstract: A method for manufacturing a semiconductor device includes (a) providing a silicon carbide semiconductor substrate; and (b) forming an electrode structure on the silicon carbide semiconductor substrate by (i) forming a Schottky layer including a metal selected from the group consisting of titanium, tungsten, molybdenum, and chrome on a front surface of the silicon carbide semiconductor substrate; (ii) heating the Schottky layer to form a Schottky electrode which has a Schottky contact with the silicon carbide semiconductor substrate; and (iii) forming a surface electrode comprised of aluminum or aluminum including silicon on a surface of the Schottky electrode, while heating at a temperature range effective for the surface electrode to closely cover any uneven portion of the Schottky electrode and provide a surface electrode having a predetermined reflectance that is equal to or less than 80% so that an improved recognition rate by an automatic wire bonding apparatus is obtained.

Abstract: A silicon carbide semiconductor device includes a low-concentration n-type drift layer deposited on a silicon carbide substrate to form a semiconductor substrate. A first front surface metal layer, which forms a Schottky contact with the semiconductor substrate, is formed on a front surface of the semiconductor substrate. An outer circumferential end of the first front surface metal layer extends on an interlayer insulating film which covers an edge portion. A second front surface metal layer which forms a front surface electrode is formed on the first front surface metal layer. When a portion of the second front surface metal layer is formed by dry etching, the entire first front surface metal layer, which will be Schottky contact metal, is covered with the second front surface metal layer. Thus, generation of an etching residue is prevented and a device with a front surface electrode structure with high reliability is provided.

Abstract: In some aspects of the invention, a layer containing titanium and nickel is formed on an SiC substrate. A nickel silicide layer containing titanium carbide can be formed by heating. A carbon layer precipitated is removed by reverse sputtering. Thus, separation of an electrode of a metal layer formed on nickel silicide in a subsequent step is suppressed. The effect of preventing the separation can be further improved when the relation between the amount of precipitated carbon and the amount of carbon in titanium carbide in the surface of nickel silicide from which the carbon layer has not yet been removed satisfies a predetermined condition.

Abstract: In a method which heats a layer including nickel and titanium on a SiC substrate (1) to form a nickel silicide layer (4) including titanium carbide, the layer including nickel and titanium is formed by vapor deposition or sputtering. The nickel silicide layer (4) is heated at a temperature that is equal to or higher than 1100° C. and equal to or less than 1350° C. to generate the layer including nickel and titanium. At that time, the rate of temperature increase is equal to greater than 10° C./minute and equal to or less than 1350° C./minute and a heating duration is equal to or more than 0 minute and equal to or less than 120 minutes. These heating conditions make it possible to obtain a homogeneous rear surface electrode (8) for a SiC semiconductor device which has sufficiently low rear surface contact resistance.

Abstract: In some aspects of the invention, a layer containing titanium and nickel is formed on an SiC substrate. A nickel silicide layer containing titanium carbide can be formed by heating. A carbon layer precipitated is removed by reverse sputtering. Thus, separation of an electrode of a metal layer formed on nickel silicide in a subsequent step is suppressed. The effect of preventing the separation can be further improved when the relation between the amount of precipitated carbon and the amount of carbon in titanium carbide in the surface of nickel silicide from which the carbon layer has not yet been removed satisfies a predetermined condition.

Abstract: A method for manufacturing a semiconductor device in which an electrode structure is formed on a silicon carbide semiconductor substrate, includes forming a Schottky layer including a metal selected from the group titanium, tungsten, molybdenum, and chrome on a front surface of the silicon carbide semiconductor substrate; heating the Schottky layer to form a Schottky electrode which has a Schottky contact with the silicon carbide semiconductor substrate; and forming a surface electrode composed of aluminum or aluminum including silicon on a surface of the Schottky electrode, while heating at a temperature range effective for the surface electrode to closely cover any uneven portion of the Schottky electrode, and provide a surface electrode having a predetermined reflectance or less that is suitable for use in an automatic wire bonding apparatus for image recognition such as positioning.

Abstract: A silicon carbide semiconductor device includes a low-concentration n-type drift layer deposited on a silicon carbide substrate to form a semiconductor substrate. A first front surface metal layer, which forms a Schottky contact with the semiconductor substrate, is formed on a front surface of the semiconductor substrate. An outer circumferential end of the first front surface metal layer extends on an interlayer insulating film which covers an edge portion. A second front surface metal layer which forms a front surface electrode is formed on the first front surface metal layer. When a portion of the second front surface metal layer is formed by dry etching, the entire first front surface metal layer, which will be Schottky contact metal, is covered with the second front surface metal layer. Thus, generation of an etching residue is prevented and a device with a front surface electrode structure with high reliability is provided.

Abstract: In a method which heats a layer including nickel and titanium on a SiC substrate (1) to form a nickel silicide layer (4) including titanium carbide, the layer including nickel and titanium is formed by vapor deposition or sputtering. The nickel silicide layer (4) is heated at a temperature that is equal to or higher than 1100° C. and equal to or less than 1350° C. to generate the layer including nickel and titanium. At that time, the rate of temperature increase is equal to greater than 10° C./minute and equal to or less than 1350° C./minute and a heating duration is equal to or more than 0 minute and equal to or less than 120 minutes. These heating conditions make it possible to obtain a homogeneous rear surface electrode (8) for a SiC semiconductor device which has sufficiently low rear surface contact resistance.

Abstract: In some aspects of the invention, a layer containing titanium and nickel is formed on an SiC substrate. A nickel silicide layer containing titanium carbide can be formed by heating. A carbon layer precipitated is removed by reverse sputtering. Thus, separation of an electrode of a metal layer formed on nickel silicide in a subsequent step is suppressed. The effect of preventing the separation can be further improved when the relation between the amount of precipitated carbon and the amount of carbon in titanium carbide in the surface of nickel silicide from which the carbon layer has not yet been removed satisfies a predetermined condition.

Abstract: A surface of a silicon carbide substrate on which a graphite layer is formed is covered with a metal layer which can form carbide. Then, the silicon carbide substrate is annealed to cause reaction between a metal in the metal layer which can form carbide and carbon in the graphite layer so as to change the graphite layer between the metal layer which can form carbide and the silicon carbide substrate to a metal carbide layer. Thus, the graphite layer is removed. The adhesion between the metal layer which can form carbide and the silicon carbide substrate can be improved so that separation of the metal layer which can form carbide can be suppressed. Graphite deposits can be suppressed due to the removal of the graphite layer so that separation of a wiring metal film formed on a surface of the metal layer which can form carbide can be suppressed.

Abstract: A solid-state image pickup element equipped with a film stack, a color filter, and a microlens on a semiconductor substrate equipped with a light receiving section, comprises a first film with a high refractive index and a second film with a low refractive index adjacently arranged on the semiconductor substrate in this order viewing from the semiconductor substrate side, each of which has at least one layer respectively. Thereby it makes possible to reduce the loss of incident light, and to achieve the enhancement in photoelectric conversion efficiency.

Abstract: An apparatus for recording and reproducing digital data according to the present invention, includes: a group converter; a controller; a recording converter; a recording unit; a reproducing unit; a reproducing converter; and a group reverse converter, wherein the group converter includes: a block management data generator for receiving the management data from the controller and generating block management data with respect to the corresponding blocked data, the block management data having a variable-length and containing information concerning each blocked data; a group management data generator for receiving the management data and generating group management data containing information concerning the entire grouped data; and a grouped data generator for receiving the blocked data, the block management data, and the group management data, and generating grouped data by arranging the blocked data, the block management data, and the group management data in a predetermined order.

Abstract: An apparatus for recording and reproducing digital data according to the present invention, includes: a group converter; a controller; a recording converter; a recording unit; a reproducing unit; a reproducing converter; and a group reverse converter, wherein the group converter includes: a block management data generator for receiving the management data from the controller and generating block management data with respect to the corresponding blocked data, the block management data having a variable-length and containing information concerning each blocked data; a group management data generator for receiving the management data and generating group management data containing information concerning the entire grouped data; and a grouped data generator for receiving the blocked data, the block management data, and the group management data, and generating grouped data by arranging the blocked data, the block management data, and the group management data in a predetermined order.

Abstract: An apparatus for recording and reproducing digital data according to the present invention, includes: a group converter; a controller; a recording converter; a recording unit; a reproducing unit; a reproducing converter; and a group reverse converter, wherein the group converter includes: a block management data generator for receiving the management data from the controller and generating block management data with respect to the corresponding blocked data, the block management data having a variable-length and containing information concerning each blocked data; a group management data generator for receiving the management data and generating group management data containing information concerning the entire grouped data; and a grouped data generator for receiving the blocked data, the block management data, and the group management data, and generating grouped data by arranging the blocked data, the block management data, and the group management data in a predetermined order.

Abstract: An apparatus for recording and reproducing digital data according to the present invention, includes: a group converter; a controller; a recording converter; a recording unit; a reproducing unit; a reproducing converter; and a group reverse converter, wherein the group converter includes: a block management data generator for receiving the management data from the controller and generating block management data with respect to the corresponding blocked data, the block management data having a variable-length and containing information concerning each blocked data; a group management data generator for receiving the management data and generating group management data containing information concerning the entire grouped data; and a grouped data generator for receiving the blocked data, the block management data, and the group management data, and generating grouped data by arranging the blocked data, the block management data, and the group management data in a predetermined order.