Sanken Electric Co., Ltd.

Junji Sato

Tetsuji Moku

Koji Otsuka

Arei Niwa

Yasuhiro Kamii

Yoshiki Tada

Mikio Tazima

Takashi Yoshida

Takashi Kato

Koji Ohtsuka

Tetsuji Matsuo

Masahiro Sato

Takasi Kato

Tomoya Sugahara

Yoshitaka Tanaka

Mikio Tajima

A light-generating semiconductor region is grown by epitaxy on a silicon substrate. The light-generating semiconductor region is a lamination of layers of semiconducting nitrides containing a Group III element or elements. The silicon substrate has a p-type impurity-diffused layer formed therein by thermal diffusion of the Group III element or elements from the light-generating semiconductor region as a secondary product of the epitaxial growth of this region on the substrate. The p-type impurity-diffused layer is utilized as a part of overvoltage protector diodes which are serially interconnected with each other and in parallel with the LED section of the device between a pair of electrodes.

Overvoltage-protected light-emitting semiconductor device, and method of fabrication

A light-emitting device has a main semiconductor region formed via an n-type AlInGaN buffer region on a p-type silicon substrate, the latter being sufficiently electroconductive to provide part of the current path through the device. Constituting the primary working part of the LED, the main semiconductor region comprises an n-type GaN layer, an active layer, and a p-type GaN layer, which are successively epitaxially grown in that order on the buffer region. A heterojunction is created between p-type substrate and n-type buffer region. Carrier transportation from substrate to buffer region is expedited by the interface levels of the heterojunction, with a consequent reduction of the drive voltage requirement of the LED.

Nitride-based semiconductor device of reduced voltage drop

A light-emitting diode is built on a silicon substrate which has been doped with a p-type impurity to possess sufficient conductivity to provide part of the current path through the LED. The p-type silicon substrate has epitaxially grown thereon a buffer region of n-type AlInGaN. Further grown epitaxially on the buffer region is the main semiconductor region of the LED which comprises a lower confining layer of n-type GaN, an active layer for generating light, and an upper confining layer of p-type GaN. In the course of the growth of the buffer region and main semiconductor region there occurs a thermal diffusion of gallium and other Group III elements from the buffer region into the p-type silicon substrate, with the consequent creation of a p-type low-resistance region in the substrate. Interface levels are created across the heterojunction between p-type silicon substrate and n-type buffer region. The interface levels expedite carrier transport from substrate to buffer region, contributing to reduction of the drive voltage requirement of the LED.

Nitride-based semiconductor device of reduced voltage drop, and method of fabrication

An LED has a light-generating semiconductor region formed on a baseplate via a metal-made reflector layer. The light-generating semiconductor region has an active layer sandwiched between a pair of claddings of opposite conductivity types. An annular marginal space is left around the reflector layer between the light-generating semiconductor region and the substrate. In order to preclude the thermal migration of the reflector metal onto the side surfaces of the light-generating semiconductor region, with a possible short-circuiting of the pair of claddings across the active layer, an anti-migration seal is received in the annular marginal space created around the reflector layer between the light-generating semiconductor region and the baseplate.

Light-emitting semiconductor device protected against reflector metal migration

An LED incorporating an overvoltage protector with a minimum of space requirement. The LED itself comprises a p-type semiconductor substrate, a light-generating semiconductor region grown epitaxially thereon, a first electrode on the light-generating semiconductor region, and a second electrode on the underside of the substrate. The standard method of LED fabrication is such that the substrate is notionally divisible into a main portion in register with the overlying light-generating semiconductor region and, surrounding the main portion, a tubular marginal portion needed for dicing the wafer into individual squares or dice. The overvoltage protector comprises an n-type semiconductor film formed on the marginal portion of the substrate and held against the side surfaces of the light-generating semiconductor region via an insulating film. Creating a pn junction with the marginal portion of the p-type substrate, the n-type semiconductor film provides an overvoltage protector diode which is electrically connected reversely in parallel with the LED. Various other embodiments are disclosed.

Overvoltage-protected light-emitting semiconductor device

There is provided a semiconductor light emitting diode and a method of manufacturing the same that enable voltage in the forward direction to be decreased while allowing light extraction efficiency to be improved. This semiconductor light emitting diode is formed by a substrate, a light emitting portion that is disposed on one main surface of the substrate, a first electrode that is disposed on the light emitting portion, a pad electrode that is disposed on the first electrode, concave portions that are formed on at least a portion of the one main surface of the substrate, and a conductive layer that is formed from a conductive material that is disposed in the concave portions and reflects light emitted from the light emitting portion.

Light emitting diode having conductive reflecting layer

A light-emitting diode is built on a silicon substrate doped with a p-type impurity to possess sufficient conductivity to provide a current path. The p-type silicon substrate has epitaxially grown thereon two superposed buffer layers of aluminum nitride and n-type indium gallium nitride. Further grown epitaxially on the buffer layers is the main semiconductor region of the LED which comprises a lower confining layer of n-type gallium nitride, an active layer for generating light, and an upper confining layer of p-type gallium nitride. In the course of the growth of the main semiconductor region there occurs a thermal diffusion of aluminum, gallium and indium from the buffer layers into the p-type silicon substrate, with the consequent creation of an alloy layer of the diffused metals. Representing p-type impurities in the p-type silicon substrate, these metals do not create a pn junction in the substrate which causes a forward voltage drop.

Nitride-based semiconductor device

A first principal plane faces a second principal plane of a p-type Ga N compound semiconductor that is in contact with an MQW luminescent layer. On the surface of the first principal plane, a first region made up of the p-type Ga N compound semiconductor including at least Ni is formed. On the surface of the first region, an electrode composed of an alloy including Ni and Aluminum is formed. On the electrode, a pad electrode for external connection consisting of Al or Au is formed.

Semiconductor luminescent device and manufacturing method thereof

For fabricating an LED substrate with minimal dislocations in its nitride semiconductor layers, GaN is epitaxially grown into a first formative layer overlying a multilayered buffer region on a silicon substrate. A second formative layer is then formed on the first formative layer by epitaxially growing AlN, at such a rate that interstices are created in the first formative layer by the etching action of the reactor gases in the early stages of the fabrication of the second formative layer. Then the second formative layer is etched away from over the intersticed first formative layer, leaving the interstices open. Then a filler layer of GaN is epitaxially grown on the intersticed first formative layer in interfitting engagement therewith. Dislocations are greatly reduced in active semiconductor layers formed subsequently on the filler layer.

Method of making substrates for nitride semiconductor devices

A light-emitting diode has a low-resistivity silicon substrate on which there are laminated a buffer layer, an n-type lower confining layer, an active layer of multiple quantum well configuration, and a p-type upper confining layer. The active layer is constituted of cyclic alternations of a barrier sublayer of InGaN, a first complementary sublayer of AlGaInN, a well sublayer of InGaN, and a second complementary sublayer of AlGaInN. The proportions of the noted ingredients of the active sublayers are all specified. The first and the second complementary sublayers prevent the evaporation or diffusion of indium from the neighboring sublayers.

Light-emitting semiconductor device having a quantum well active layer, and method of fabrication

An overvoltage-proof light-emitting diode has a lamination of light-generating semiconductor layers on a first major surface of a silicon substrate. A front electrode in the form of a bonding pad is mounted centrally atop the light-generating semiconductor layers whereas a back electrode covers a second major surface of the substrate. An overvoltage protector, of which several different forms are disclosed, is disposed between the bonding pad and the second major surface of the substrate. The bonding pad and back electrode serves as electrodes for both LED and overvoltage protector. As seen from above the device, or in a direction normal to the first major surface of the substrate, the overvoltage protector lies substantially wholly beneath the bonding pad.

Light-emitting semiconductor device with a built-in overvoltage protector

A semiconductor substrate for a light-emitting diode, heterojunction transistor or the like. Included is a buffer region of an aluminum-containing nitride or the like grown epitaxially on a baseplate of silicon or a silicon compound. A dislocation-refracting region of an indium-containing nitride is grown epitaxially on the buffer region in order to provide a major surface having a multiplicity of protuberances of pyramidal shape capable of refracting the dislocations created in the buffer region. A leveling region of a nitride, not containing indium, is formed on the major surface of the dislocation refracting region in order to provide a major surface of greater levelness than the transition refracting region. The leveling region is reduced in dislocation density owing to the interposition of the dislocation refracting region between buffer region and leveling region.

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Niiza, Japan

Junji Sato