Abstract: According to an embodiment, a memory system includes memory chips operable in parallel and a memory controller. The memory chips each include first storage areas. The memory controller generates first groups each including first storage areas selected from different memory chips. The memory controller generates second groups each being constituted by a minimum number of first storage areas composed by excluding one or more first storage areas from each of the first groups. The minimum number of first storage areas are capable of storing at least a first amount of data received from the host. The memory controller executes writing of the data to all the minimum number of first storage areas constituting one second group.

Abstract: First and second p-type semiconductor regions (electric-field relaxation layers) are formed by ion implantation using a dummy gate and side wall films on both sides of the dummy gate as a mask. In this manner, it is possible to reduce a distance between the first p-type semiconductor region and a trench and a distance between the second p-type semiconductor region and the trench, and symmetry of the first and second p-type semiconductor regions with respect to the trench can be enhanced. As a result, semiconductor elements can be miniaturized, and on-resistance and an electric-field relaxation effect, which are in a trade-off relationship, can be balanced, so that characteristics of the semiconductor elements can be improved.

Abstract: First and second p-type semiconductor regions (electric-field relaxation layers) are formed by ion implantation using a dummy gate and side wall films on both sides of the dummy gate as a mask. In this manner, it is possible to reduce a distance between the first p-type semiconductor region and a trench and a distance between the second p-type semiconductor region and the trench, and symmetry of the first and second p-type semiconductor regions with respect to the trench can be enhanced. As a result, semiconductor elements can be miniaturized, and on-resistance and an electric-field relaxation effect, which are in a trade-off relationship, can be balanced, so that characteristics of the semiconductor elements can be improved.

Abstract: According to an embodiment, a memory system includes memory chips operable in parallel and a memory controller. The memory chips each include first storage areas. The memory controller generates first groups each including first storage areas selected from different memory chips. The memory controller generates second groups each being constituted by a minimum number of first storage areas composed by excluding one or more first storage areas from each of the first groups. The minimum number of first storage areas are capable of storing at least a first amount of data received from the host. The memory controller executes writing of the data to all the minimum number of first storage areas constituting one second group.

Abstract: A drift layer is formed over a semiconductor substrate which is an SiC substrate. The drift layer includes first to third n-type semiconductor layers and a p-type impurity region. Herein, an impurity concentration of the second n-type semiconductor layer is higher than an impurity concentration of the first n-type semiconductor layer and an impurity concentration of the third n-type semiconductor layer. Also, in plan view, the second semiconductor layer located between the p-type impurity regions adjacent to each other overlaps with at least a part of a gate electrode formed in a trench.

Abstract: A Semiconductor device includes a substrate and a thermal conductive film. The substrate has a top surface and a back surface which oppose with each other. A first opening is formed on the back surface of substrate. The thermal conductive film includes a first thermal conductive portion formed in the first opening. The first thermal conductive portion is embedded in the first opening such that a void is formed in the first opening.

Abstract: A gallium oxide diode includes: a gallium oxide substrate having an n-type gallium oxide drift layer; an anode electrode of a metal film formed over a front surface of the n-type gallium oxide drift layer; a cathode electrode formed over a rear surface of the gallium oxide substrate; and a reaction layer of a metal oxide film of p-type conductivity formed between the anode electrode and the n-type gallium oxide drift layer. Further, a manufacturing method of a gallium oxide diode includes steps of forming an anode electrode of a metal film over an n-type gallium oxide drift layer formed over a gallium oxide substrate; and forming a reaction layer between the anode electrode and the n-type gallium oxide drift layer by performing a heat treatment to the gallium oxide substrate after forming the anode electrode, the reaction layer being made of a metal oxide film with p-type conductivity.

Abstract: First and second p-type semiconductor regions (electric-field relaxation layers) are formed by ion implantation using a dummy gate and side wall films on both sides of the dummy gate as a mask. In this manner, it is possible to reduce a distance between the first p-type semiconductor region and a trench and a distance between the second p-type semiconductor region and the trench, and symmetry of the first and second p-type semiconductor regions with respect to the trench can be enhanced. As a result, semiconductor elements can be miniaturized, and on-resistance and an electric-field relaxation effect, which are in a trade-off relationship, can be balanced, so that characteristics of the semiconductor elements can be improved.

Abstract: A Semiconductor device includes a substrate and a thermal conductive film. The substrate has a top surface and a back surface which oppose with each other. A first opening is formed on the back surface of substrate. The thermal conductive film includes a first thermal conductive portion formed in the first opening. The first thermal conductive portion is embedded in the first opening such that a void is formed in the first opening.

Abstract: First and second p-type semiconductor regions (electric-field relaxation layers) are formed by ion implantation using a dummy gate and side wall films on both sides of the dummy gate as a mask. In this manner, it is possible to reduce a distance between the first p-type semiconductor region and a trench and a distance between the second p-type semiconductor region and the trench, and symmetry of the first and second p-type semiconductor regions with respect to the trench can be enhanced. As a result, semiconductor elements can be miniaturized, and on-resistance and an electric-field relaxation effect, which are in a trade-off relationship, can be balanced, so that characteristics of the semiconductor elements can be improved.

Abstract: An n-type epitaxial layer is formed on an n-type semiconductor substrate made of silicon carbide. p-type body regions are formed in the epitaxial layer, and n-type source region is formed in the body region. On the body region between the source region and the epitaxial layer, a gate electrode is formed via a gate dielectric film, and an interlayer insulating film having an opening is formed so as to cover the gate electrode. A source electrode electrically connected to the source region and the body regions is formed in the opening. A recombination layer is formed between the body region and a basal plane dislocation is a layer having point defect density higher than that of the epitaxial layer located directly under the recombination layer or having a metal added to the epitaxial layer.

Abstract: Characteristics of a semiconductor device using a nitride semiconductor are improved. A semiconductor device of the present invention includes a buffer layer, a channel layer, a barrier layer, a mesa-type 2DEG dissolving layer, a source electrode, a drain electrode, a gate insulating film formed on the mesa-type 2DEG dissolving layer, and an overlying gate electrode. The gate insulating film of the semiconductor device includes a sputtered film formed on the mesa-type 2DEG dissolving layer and a CVD film formed on the sputtered film. The sputtered film is formed in a non-oxidizing atmosphere by a sputtering process using a target including an insulator. This makes it possible to reduce positive charge amount at a MOS interface and in gate insulating film and increase a threshold voltage, and thus improve normally-off characteristics.

Abstract: First and second p-type semiconductor regions (electric-field relaxation layers) are formed by ion implantation using a dummy gate and side wall films on both sides of the dummy gate as a mask. In this manner, it is possible to reduce a distance between the first p-type semiconductor region and a trench and a distance between the second p-type semiconductor region and the trench, and symmetry of the first and second p-type semiconductor regions with respect to the trench can be enhanced. As a result, semiconductor elements can be miniaturized, and on-resistance and an electric-field relaxation effect, which are in a trade-off relationship, can be balanced, so that characteristics of the semiconductor elements can be improved.

Abstract: A semiconductor device includes a first nitride semiconductor layer formed over a substrate, a second nitride semiconductor layer formed over the first nitride semiconductor layer and having a band gap wider than a band gap of the first nitride semiconductor layer, a trench penetrating through the second nitride semiconductor layer and reaching an inside of the first nitride semiconductor layer, a gate electrode placed in the trench over a gate insulating film, and a first electrode and a second electrode formed over the second nitride semiconductor layer on both sides of the gate electrode, respectively.

Abstract: A semiconductor device includes a codoped layer, a channel layer, a barrier layer, and a gate electrode disposed in a trench extending through the barrier layer and reaching a middle point in the channel layer via a gate insulating film. On both sides of the gate electrode, a source electrode and a drain electrode are formed. On the source electrode side, an n-type semiconductor region is disposed to fix a potential and achieve a charge removing effect while, on the drain electrode side, a p-type semiconductor region is disposed to improve a drain breakdown voltage. By introducing hydrogen into a region of the codoped layer containing Mg as a p-type impurity in an amount larger than that of Si as an n-type impurity where the n-type semiconductor region is to be formed, it is possible to inactivate Mg and provide the n-type semiconductor region.

Abstract: A drift layer is formed over a semiconductor substrate which is an SiC substrate. The drift layer includes first to third n-type semiconductor layers and a p-type impurity region. Herein, an impurity concentration of the second n-type semiconductor layer is higher than an impurity concentration of the first n-type semiconductor layer and an impurity concentration of the third n-type semiconductor layer. Also, in plan view, the second semiconductor layer located between the p-type impurity regions adjacent to each other overlaps with at least a part of a gate electrode formed in a trench.

Abstract: Properties of a semiconductor device are improved. A semiconductor device is configured so as to include a voltage clamp layer, a channel underlayer, a channel layer, and a barrier layer, which are formed in order above a substrate, a trench that extends up to the middle of the channel layer while penetrating through the barrier layer, a gate electrode disposed within the trench with a gate insulating film in between, a source electrode and a drain electrode formed above the barrier layer on both sides of the gate electrode, and a fourth electrode electrically coupled to the voltage clamp layer. The fourth electrode is electrically isolated from the source electrode, and a voltage applied to the fourth electrode is different from a voltage applied to the source electrode. Consequently, threshold control can be performed. For example, a threshold of a MISFET can be increased.

Abstract: A property of a semiconductor device (high electron mobility transistor) is improved. A semiconductor device having a buffer layer, a channel layer, an electron supply layer, a mesa type cap layer, a source electrode, a drain electrode and a gate insulating film covering the cap layer, and a gate electrode formed on the gate insulating film, is configured as follows. The cap layer and the gate electrode are separated from each other by the gate insulating film, and side surfaces of the cap layer, the side surfaces being closer to the drain electrode and the source electrode, have tapered shapes. For example, a taper angle (?1) of the side surface of the cap layer (mesa portion) is equal to or larger than 120 degrees. By this configuration, a TDDB life can be effectively improved, and variation in an ON-resistance can be effectively suppressed.

Abstract: Characteristics of a semiconductor device are improved. A semiconductor device of the present invention includes a buffer layer composed of a first nitride semiconductor layer, a channel layer composed of a second nitride semiconductor layer, and a barrier layer composed of a third nitride semiconductor layer, which are sequentially laminated, and a cap layer composed of a fourth nitride semiconductor layer of mesa type, which is formed over the barrier layer. The semiconductor device also includes a source electrode formed on one side of the cap layer, a drain electrode formed on the other side of the cap layer, and a first gate electrode formed over the cap layer. The first gate electrode and the cap layer are Schottky-joined. A Schottky gate electrode (the first gate electrode) is provided over the cap layer in this way, so that when a gate voltage is applied, an electric field is applied to the entire cap layer and a depletion layer spreads. Therefore, it is possible to suppress a gate leakage current.

Abstract: A mesa portion of a semiconductor device, which includes a channel base layer formed of a first nitride semiconductor layer, a channel layer formed of a second nitride semiconductor layer, a barrier layer formed of a third nitride semiconductor layer, a mesa-type fourth nitride semiconductor layer, a gate insulating film that covers the mesa portion, and a gate electrode formed over the gate insulating film, is used as a co-doped layer. The mesa portion is used as the co-doped layer, so that interface charges generated at an interface between the gate insulating film and the mesa portion can be cancelled by p-type impurity or n-type impurity in the co-doped layer and a threshold potential can be improved. Further, the fourth nitride semiconductor layer is n-type until the gate insulating film is formed, and the fourth nitride semiconductor layer is made neutral or p-type after the gate insulating film is formed.