Abstract: Provided is a semiconductor device that can reduce the contact resistance, has a small current collapse, and can improve the pinch-off characteristic upon a high-frequency operation. A field effect transistor using a wurtzite (having (0001) as the main plane) type III-nitride semiconductor includes: a substrate (101); an undercoat layer (103) of a first III-nitride semiconductor; and a carrier travel layer (104) of a second III-nitride semiconductor. The undercoat layer (103) (101) and the carrier travel layer (104) is formed on the substrate in this order. The field effect transistor includes source/drain electrodes (105, 106) in ohmic contact, and a gate electrode (107) in Schottky contact directly or via another layer on the carrier travel layer (104). The undercoat layer (103) has an average lattice constant greater than that of the carrier travel layer (104) and a band gap greater than that of the carrier travel layer (104).

Abstract: A first log indicating that a system is running is recorded in a second storage unit before a first difference log is recorded in the second storage unit after system startup, and a second log indicating that the system halts is recorded in the second storage unit following the difference log, at the time of normal system halt, and it is judged whether normal system halt has been performed or an incorrect power-off sequence has been performed last time, based on a recorded state of the first and second logs in the second storage unit, at the time of system startup, thereby detecting an incorrect power-off easily and reliably.

Abstract: A field plate portion (5) overhanging a drain side in a visored shape is formed in a gate electrode (2). A multilayered film including a SiN film (21) and a SiO2 film (22) is formed beneath the field plate portion (5). The SiN film (21) is formed so that a surface of an AlGaN electron supply layer (13) is covered therewith.

Abstract: The present invention provides a semiconductor device that has high electron mobility while reducing a gate leakage current, and superior uniformity and reproducibility of the threshold voltage, and is also applicable to the enhancement mode type.

Abstract: A field effect transistor (100) exhibiting good performance at high voltage operation and high frequency includes a first field plate electrode (116) and a second field plate electrode (118). The second field plate electrode includes a shielding part (119) located in the region between the first field plate electrode and a drain electrode (114), and serves to shield the first field plate electrode from the drain electrode. When in the cross sectional view in the gate length direction, the length in the gate length direction of an overlap region where the second field plate electrode (118) overlap the upper part of a structure including the first field plate electrode and a gate electrode (113) is designated as Lol, and the gate length is Lg, the relation expressed as 0 ?Lol/Lg?1 holds.

Abstract: A semiconductor device capable of suppressing the occurrence of a punch-through phenomenon is provided. A first n-type conductive layer (2?) is formed on a substrate (1?). A p-type conductive layer (3?) is formed thereon. A second n-type conductive layer (4?) is formed thereon. On the under surface of the substrate (1?), there is a drain electrode (13?) connected to the first n-type conductive layer (2?). On the upper surface of the substrate (1?), there is a source electrode (11?) in ohmic contact with the second n-type conductive layer (4?), and a gate electrode (12?) in contact with the first n-type conductive layer (2?), p-type conductive layer (3?), the second n-type conductive layer (4?) through an insulation film (21?). The gate electrode (12?) and the source electrode (11?) are alternately arranged. The p-type conductive layer (3?) includes In.

Abstract: The present invention provides a semiconductor device capable of suppressing current collapse, and also of preventing dielectric breakdown voltage and gain from lowering so as to perform high-voltage operation and realize an ideal high output. On a substrate (101), there are formed a buffer layer (102) made of a first GaN-based semiconductor, a carrier traveling layer (103) made of a second GaN-based semiconductor and a carrier supplying layer (104) made of a third GaN-based semiconductor. A recess structure (108) is made by eliminating a part of a first insulation film (107) and a part of the carrier supplying layer (104). Next, a gate insulation film (109) is deposited, and then a gate electrode (110) is formed so as to fill up the recess portion (108) and cover on over an area where the first insulation film (107) remains so that its portion on the drain electrode side is longer than that on the source electrode side.

Abstract: A semiconductor device includes a lower barrier layer 12 composed of a layer of AlxGa1-xN (0?x?1) in a state of strain relaxation, and a channel layer 13, which is composed of a layer of InyGa1-yN (0?y?1) disposed on the lower barrier layer 12, has band gap that is smaller than band gap of the lower barrier layer 12, and exhibits compressive strain. A gate electrode 1G is formed over the channel layer 13 via an insulating film 15 and a source electrode 1S and a drain electrode 1D serving as ohmic electrodes are formed over the channel layer 13. The insulating film 15 is constituted of polycrystalline or amorphous member.

Abstract: A field effect transistor includes a layer structure made of compound semiconductor (111) provided on a semiconductor substrate (110) made of GaAs or InP, as an operation layer, and employs a first field plate electrode (116) and a second field plate electrode (118). The second field plate electrode includes a shielding part (119) located in the region between the first field plate electrode and a drain electrode (114), and serves to shield the first field plate electrode from the drain electrode. When, in the cross sectional view in the gate length direction, the length in the gate length direction of an overlap region, in which the second field plate electrode overlaps the upper part of a structure composed of the first field plate electrode and a gate electrode (113), is designated as Lol, and the gate length is Lg, the relation expressed as 0?Lol/Lg?1 holds.

Abstract: A semiconductor device includes a channel layer, an electron-supplying layer provided on the channel layer, a cap layer provided on the electron-supplying layer and creating lattice match with the channel layer, and ohmic electrodes provided on the cap layer. The cap layer has a composition of (InyAl1-y)zGa1-zN (0?y?1, 0?z?1). The z for such cap layer monotonically decreases as being farther away from the electron-supplying layer.

Abstract: Disclosed is an HJFET 110 which comprises: a channel layer 12 composed of InyGa1-yN (0?y?1); a carrier supply layer 13 composed of AlxGa1-xN (0?x?1), the carrier supply layer 13 being provided over the channel layer 12 and including at least one p-type layer; and a source electrode 15S, a drain electrode 15D and a gate electrode 17 which are disposed facing the channel layer 12 through the p-type layer, and provided over the carrier supply layer 13. The following relational expression is satisfied: 5.6×1011x<NA×?×t [cm?2]<5.6×1013x, where x denotes an Al compositional ratio of the carrier supply layer, t denotes a thickness of the p-type layer, NA denotes an impurity concentration, and ? denotes an activation ratio.

Abstract: A memory system in which a first management unit includes an update information managing unit that manages update information indicating an updated section in status information stored in a volatile first storing unit, and an update information notifying unit that notifies a second management unit of the update information managed by the update information managing unit, and the second management unit includes a commit executing unit that collects, based on the update information, difference information of the status information from the status area when the update information is notified from the update information notifying unit, and causes a second storing unit to accumulate the difference information in a backup area.

Abstract: A memory system according to an embodiment of the present invention comprises: a log overflow control unit that, when a third condition in which a second log accumulated in a log storage area exceeds a set value is satisfied, stops a recording operation of the second log in the log storage area by a log recording unit and causes a log recording unit to perform an update operation of a second management table in a master table and a recording operation of a first log in the log storage area, and that, when a first condition is satisfied next time, prohibits a commit operation by a log reflecting unit and causes a snapshot storing unit to perform a snapshot storing operation.

Abstract: In a field effect transistor, a Group III nitride semiconductor layer structure containing a hetero junction, a source electrode 101 and a drain electrode 103 formed apart from each other over the Group III nitride semiconductor layer structure, and a gate electrode 102 disposed between these electrodes, are provided. Over the surface of the Group III nitride semiconductor layer structure, a SiO2 film 122 containing oxygen as a constitutive element is provided, in contact with both side faces of the gate electrode 102. Over the surface of the Group III nitride semiconductor layer structure, a SiN film 121 is provided so as to cover the region between the SiO2 film 122 and the source electrode 101, and the region between the SiO2 film 122 and the drain electrode 103. The SiN film 121 is composed of a material different from that composing the SiO2 film 122, and contains nitrogen as a constitutive element.

Abstract: Provided is a semiconductor device that can reduce the contact resistance, has a small current collapse, and can improve the pinch-off characteristic upon a high-frequency operation. A field effect transistor using a wurtzite (having (0001) as the main plane) type III-nitride semiconductor includes: a substrate (101); an undercoat layer (103) of a first III-nitride semiconductor; and a carrier travel layer (104) of a second III-nitride semiconductor. The undercoat layer (103) (101) and the carrier travel layer (104) is formed on the substrate in this order. The field effect transistor includes source/drain electrodes (105, 106) in ohmic contact, and a gate electrode (107) in Schottky contact directly or via another layer on the carrier travel layer (104). The undercoat layer (103) has an average lattice constant greater than that of the carrier travel layer (104) and a band gap greater than that of the carrier travel layer (104).

Abstract: A semiconductor device, comprising: a semiconductor element 20 having a rectangular two-dimensional geometry and serving as a heat source; and a heat sink section 25 having the semiconductor element 20 mounted thereon, wherein a relation among the directional components of said thermal conductivity is: Kzz?Kyy>Kxx, where directional components of three-dimensional thermal conductivity of the heat sink section 25 in X, Y and Z directions are determined as Kxx, Kyy and Kzz, and where the longer side direction of the semiconductor element 20 is defined as X direction, the shorter side direction thereof is defined as Y direction and the thickness direction is defined as Z direction.

Abstract: There is provided a technology for obtaining an electrode having a low contact resistance and less surface roughness. There is provided an electrode comprising a semiconductor film 101, and a first metal layer 102 and a second metal layer 103 sequentially stacked in this order on the semiconductor film 101, characterized in that the first metal film 102 is formed of Al, and the second metal film 103 is formed of at least one metal selected from the group consisting of Nb, W, Fe, Hf, Re, Ta and Zr.

Abstract: A field effect transistor 100 includes a group III-V nitride semiconductor layer structure containing a hetero junction, a source electrode 105 and a drain electrode 106 formed on the group III-V nitride semiconductor layer structure to be spaced apart from each other; a gate electrode 110 arranged between the source electrode 105 and the drain electrode 106, and an insulating layer 107 provided over, and in contact with, the group III-V nitride semiconductor layer structure in a region between the gate electrode 110 and the drain electrode 106 or in a region between the source electrode 105 and the gate electrode 110. A portion of the gate electrode 110 is buried in the group III-V nitride semiconductor layer structure, and a side edge of the gate electrode in an interface of the group III-V nitride semiconductor layer and the insulating layer 107 is spaced apart from the gate electrode 110.

Abstract: A field effect transistor (100) exhibiting good performance at high voltage operation and high frequency includes a first field plate electrode (116) and a second field plate electrode (118). The second field plate electrode includes a shielding part (119) located in the region between the first field plate electrode and a drain electrode (114), and serves to shield the first field plate electrode from the drain electrode. When in the cross sectional view in the gate length direction, the length in the gate length direction of an overlap region where the second field plate electrode (118) overlap the upper part of a structure including the first field plate electrode and a gate electrode (113) is designated as Lol, and the gate length is Lg, the relation expressed as 0?Lol/Lg?1 holds.

Abstract: A field effect transistor includes a layer structure made of compound semiconductor (111) provided on a semiconductor substrate (110) made of GaAs or InP, as an operation layer, and employs a first field plate electrode (116) and a second field plate electrode (118). The second field plate electrode includes a shielding part (119) located in the region between the first field plate electrode and a drain electrode (114), and serves to shield the first field plate electrode from the drain electrode. When, in the cross sectional view in the gate length direction, the length in the gate length direction of an overlap region, in which the second field plate electrode overlaps the upper part of a structure composed of the first field plate electrode and a gate electrode (113), is designated as Lol, and the gate length is Lg, the relation expressed as 0?Lol/Lg?1 holds.