Other

Kabushiki Kaisha Toyota Chuo Kenkyusho

Toyoda Gosei Co., Ltd.

Nagoya University

Research Development Corporation of Japan

Denso Corporation

Japan Science and Technology Agency

Masafumi Hashimoto

Katsuhide Manabe

Norikatsu Koide

Isamu Akasaki

Shiro Yamazaki

Hisaki Kato

Akira Mabuchi

Michinari Sassa

Masahiro Kotaki

Hiroyuki Kano

Makoto Tamaki

Nobuhiko Sawaki

Kiyokazu Takagi

Takatoshi Kato

Masaki Mori

An apparatus having a laser radar is used to recognize a pedestrian by detecting a position of reflective objects, mapping the objects in a two-dimensional coordinate system, determining whether the objects are moving, and grouping moving objects closely located with each other. Based on a size of an object group, the pedestrian associated with the object group is accurately recognized.

Apparatus and method of pedestrian recognition

Disclosed herein are (1) a light-emitting semiconductor device that uses a gallium nitride compound semiconductor (AlGaN) in which the n-layer of n-type gallium nitride compound semiconductor (AlGaN) is of double-layer structure including an n-layer of low carrier concentration and an n-layer of high carrier concentration, the former being adjacent to the i-layer of insulating gallium nitride compound semiconductor (AlGaN); (2) a light-emitting semiconductor device of similar structure as above in which the i-layer is of double-layer structure including an i-layer of low impurity concentration containing p-type impurities in comparatively low concentration and an i-layer of high impurity concentration containing p-type impurities in comparatively high concentration, the former being adjacent to the n-layer; (3) a light-emitting semiconductor device having both of the above-mentioned features and (4) a method of producing a layer of an n-type gallium nitride compound semiconductor (AlGaN) having a controlled conductivity from an organometallic compound by vapor phase epitaxy, by feeding a silicon-containing gas and other raw material gases together at a controlled mixing ratio.

Method for manufacturing a gallium nitride group compound semiconductor

Disclosed herein are (1) a light-emitting semiconductor device that uses a gallium nitride compound semiconductor (Al Ga N) in which the n-layer of n-type gallium nitride compound semiconductor (Al Ga N) is of double-layer structure including an n-layer of low carrier concentration and an n -layer of high carrier concentration, the former being adjacent to the i-layer of insulating gallium nitride compound semiconductor (Al Ga N); (2) a light-emitting semiconductor device of similar structure as above in which the i-layer is of double-layer structure including an i -layer of low impurity concentration containing p-type impurities in comparatively low concentration and an i -layer of high impurity concentration containing p-type impurities in comparatively high concentration, the former being adjacent to the n-layer; (3) a light-emitting semiconductor device having both of the above-mentioned features and (4) a method of producing a layer of an n-type gallium nitride compound semiconductor (Al Ga N) having a controlled conductivity from an organometallic compound by vapor phase epitaxy, by feeding a silicon-containing gas and other raw material gases together at a controlled mixing ratio.

Light-emitting semiconductor device using gallium nitride group compound

Gallium nitride group compound semiconductor

Light emitting device

A semiconductor device having an n-type layer of gallium nitride that is doped with silicon and has a resistively ranging from 3&times;10,&OHgr;cm to 8&times;,&OHgr;cm or a carrier concentration ranging from 6&times;10,/cm,to 3&times;10,/cm,.

Light emitting semiconductor device using gallium nitride group compound

A light-emitting semiconductor device using a gallium nitride compound semiconductor (Al.sub.x Ga.sub.1-x N) having an i.sub.L -layer of insulating gallium nitride compound semiconductor (Al.sub.x Ga.sub.1-x N, inclusive of x=0) containing a low concentration of p-type impurities. An i.sub.H -layer of insulating gallium nitride compound semiconductor (Al.sub.x Ga.sub.1-x N, inclusive of x=0) containing a high concentration of p-type impurities is adjacent to the i.sub.L -layer. An n-layer of n-type gallium nitride compound semiconductor (Al.sub.x Ga.sub.1-x N, inclusive of x=0) of low carrier concentration is adjacent to the i.sub.L -layer. An n.sup.+ -layer of n-type gallium nitride compound semiconductor (Al.sub.x Ga.sub.1-x N, inclusive of x=0) of high carrier concentration doped with n-type impurities is adjacent to the n-layer.

A light-emitting diode of GaN compound semiconductor emits a blue light from a plane rather than dots for improved luminous intensity. This diode includes a first electrode associated with a high-carrier density n.sup.+ layer and a second electrode associated with a high-impurity density i.sub.H -layer. These electrodes are made up of a first Ni layer (110 .ANG. thick), a second Ni layer (1000 .ANG. thick), an Al layer (1500 .ANG. thick), a Ti layer (1000 .ANG. thick), and a third Ni layer (2500 .ANG. thick). The Ni layers of dual structure permit a buffer layer to be formed between them. This buffer layer prevents the Ni layer from peeling. The direct contact of the Ni layer with GaN lowers a drive voltage for light emission and increases luminous intensity.

Light-emitting device of gallium nitride compound semiconductor

Disclosed herein are (1) a light-emitting semiconductor device that uses a gallium nitride compound semiconductor (Al.sub.x Ga.sub.1-x N) in which the n-layer of n-type gallium nitride compound semiconductor (Al.sub.x Ga.sub.1-x N) is of double-layer structure including an n-layer of low carrier concentration and an n.sup.+ -layer of high carrier concentration, the former being adjacent to the i-layer of insulating gallium nitride compound semiconductor (Al.sub.x Ga.sub.1-x N); (2) a light-emitting semiconductor device of similar structure as above in which the i-layer is of double-layer structure including an i.sub.L -layer of low impurity concentration containing p-type impurities in comparatively low concentration and an i.sub.H -layer of high impurity concentration containing p-type impurities in comparatively high concentration, the former being adjacent to the n-layer; (3) a light-emitting semiconductor device having both of the above-mentioned features and (4) a method of producing a layer of an n-type gallium nitride compound semiconductor (Al.sub.x Ga.sub.1-x N) having a controlled conductivity from an organometallic compound by vapor phase epitaxy, by feeding a silicon-containing gas and other raw material gases together at a controlled mixing ratio.

A dry etching method for Al.sub.x Ga.sub.1-x N (0.ltoreq.x.ltoreq.1) semiconductor uses plasma of a boron trichloride (BCl.sub.3) gas. The etching rate of the method is 490 .ANG./min. No crystal defect is produced in the etched semiconductor by the dry etching with the plasma of a BCl.sub.3 gas. After etching with the plasma of a BCl.sub.3 gas, the semiconductor is successively etched by an inert gas. The electrode formed on the etched surface is contacted ohmicly with the semiconductor. Ohmic contact can be obtained without sintering. An LED is produced by the dry etching method. The LED comprises a substrate, an n-layer (Al.sub.x Ga.sub.1-x N; 0.ltoreq.x&lt;1), an i-layer, an electrode formed on the etched surface of the n-layer through a through hole, the through hole being formed through the i-layer to the n-layer by the dry etching with the plasma of the born trichloride (BCl.sub.3) gas and being successively etched by the plasma of an inert gas, and an electrode formed on the surface of said i-layer.

Dry etching method for semiconductor

A dry etching method for Al.sub.x Ga.sub.1-x N(0.ltoreq.x.ltoreq.1) semiconductor is disclosed. The method includes a first method using plasma of carbon tetrachloride (CCl.sub.4) gas, and a second method using plasma of dichlorodifluoromethane (CCl.sub.2 F.sub.2) gas. The etching speed of the former method was 430 .ANG./min. and the etching speed of the latter method was 625 .ANG./min. Also, no crystal defect was produced in the above-mentioned semiconductor by the above-mentioned etching.

A compound semiconductor device comprises a substrate formed from a single crystal of silicon, a layer of an insulator formed on a portion of a surface of the substrate, at least one layer of a high resistance compound semiconductor formed on the insulator layer, and at least one layer of a single crystal of a compound semiconductor formed on a different portion of the substrate surface from the insulator layer. The device can be manufactured by forming an insulator layer on one portion of a surface of a single crystal silicon substrate, and growing a compound semiconductor by epitaxy on the insulator layer and on the different portion from the insulator layer. One of useful applications is a hybrid semiconductor device having a compound semiconductor formed from e.g. GaAs on a silicon substrate.

Compound semiconductor device and a method of manufacturing the same

A semiconductor device having a superlattice structure, which comprises at least one unit structure including first and third semiconductor layers as quantum well layers, and a second semiconductor layer as a barrier layer, which are arranged alternately on each other is described. The first semiconductor layer has a higher impurity concentration than the third semiconductor layer and has a quantum energy level determined by its thickness. The third semiconductor layer is of a thickness having quantum energy levels, one of which is lower than that of the first semiconductor layer and the second of which is equal to or higher than that of the first semiconductor layer. The second semiconductor layer is of a thickness which allows electrons existing at the second quantum energy level of the third semiconductor layer to transfer easily from the third to the first semiconductor layer. An increase in voltage applied to the semiconductor device causes electrons to transfer to the first semiconductor layer through the second quantum energy level of the third semiconductor layer to reduce the mobility of electrons in the first semiconductor layer, thus causing the semiconductor device to develop a negative resistance.

Growing community of inventors

Nagoya, Japan

Masafumi Hashimoto