Light-emitting device, method of fabricating the same, and OHMIC electrode structure for semiconductor device

A light-emitting device comprising:

• a light-emitting layer portion being composed of a first compound semiconductor, having an emission peak wavelength of 450 to 580 nm, and having a light extraction surface on the main surface side thereof;
• an Ag-base contact layer formed on the main back surface of the light-emitting layer portion, or formed on the main back surface of an auxiliary compound semiconductor layer composed of a second compound semiconductor, which is transparent with respect to emission light flux and is electrically coupled to the main back surface of the light-emitting layer portion, the Ag-base contact layer comprising an alloyed layer originated from an Ag-base contact metal, having Ag as a major component, and the compound semiconductor composing the main back surface of the compound semiconductor layer;
• and
• an Ag-base reflective metal layer, composed of a metal having Ag as a major component, for reflecting light from the light-emitting layer portion back towards the light extraction surface side, and being formed so as to cover the Ag-base contact layer.

A light-emitting device comprising:

• a compound semiconductor layer having a light-emitting layer portion, being configured so that a first main surface of which serves as a light extraction surface;
• and
• a device substrate bonded on a second main surface side of the compound semiconductor layer while placing a main metal layer in between, the main metal layer having a reflective surface for reflecting light from the light-emitting layer portion back towards the light extraction surface side;
• further comprising:
• a diffusion-blocking layer interposed between the device substrate and the main metal layer, being composed of a conductive material, and provided for blocking diffusion of any device-substrate-derived components towards the main metal layer.

A method of fabricating a light-emitting device, the device comprising:

• a compound semiconductor layer having a light-emitting layer portion, being configured so that a first main surface of which serves as a light extraction surface;
• and
• a device substrate bonded on a second main surface side of the compound semiconductor layer while placing a main metal layer in between, the main metal layer having a reflective surface for reflecting light from the light-emitting layer portion back towards the light extraction surface side;
• the method comprising the steps of:
• forming a diffusion-blocking layer on the main surface of the device substrate on the side the compound semiconductor layer is to be bonded, being composed of a conductive material and planned for blocking diffusion of any device-substrate-derived components towards the main metal layer;
• forming the main metal layer on at least either one of the second main surface of the compound semiconductor layer, and the main surface of the diffusion-blocking layer formed on the device substrate;
• and
• bonding the device substrate and the compound semiconductor layer while placing the diffusion-blocking layer and the main metal layer in between.

A method of fabricating a light-emitting device, the device comprising:

• a compound semiconductor layer having a light-emitting layer portion, being configured so that one main surface of which serves as a light extraction surface;
• and
• a device substrate bonded on the other main surface side of the compound semiconductor layer while placing a metal layer in between, the metal layer having a reflective surface for reflecting light from the light-emitting layer portion back towards the light extraction surface side, and the metal layer being composed of an Au-base layer having Au as a major component at least in a portion thereof including the reflective surface;
• the method comprising the steps of:
• disposing a first Au-base layer on a bonding-side main surface of the compound semiconductor layer, the bonding-side main surface being defined as the main surface opposite to that planned for becoming the light extraction surface;
• disposing a second Au-base layer on the bonding-side main surface of the device substrate, the bonding-side main surface being defined as the main surface which is planned to be disposed on the light-emitting-layer-portion side;
• and
• bonding the first Au-base metal layer and the second Au-base metal layer under a close contact.

A method of fabricating the light emitting device, the device comprising:

• a compound semiconductor layer having a light-emitting layer portion, being configured so that a first main surface of which serves as a light extraction surface;
• and
• a Si substrate bonded on a second main surface side of the compound semiconductor layer while placing a metal layer in between, wherein the bonding surface between the metal layer and the compound semiconductor layer configures a reflective layer;
• the method comprising the steps of:
• forming the metal layer as having a Si-diffusion-blocking layer which has Au or Ag as a major component and also contains a Si-diffusion-blocking component which comprises a single, or two or more elements selected from Sn, Pb, In and Ga, and being planned for inhibiting Si diffused from the Si substrate from depositing on the reflective surface;
• and
• bonding the Si substrate and the compound semiconductor layer while placing the metal layer in between.