GaN LED with solderable backside metal

A method for fabricating a light-emitting element, the method comprising:

• depositing semiconducting layers on a front side of an electrically insulating substrate such that the semiconducting layers define a light-emissive region that emits light responsive to an electrical current flowing therethrough;
• forming electrical contacts contacting selected semiconducting layers;
• depositing a metallic bonding layer on a back side of the substrate, the depositing of a metallic bonding layer including:
• depositing a silver layer on the substrate,
• depositing a second layer onto the silver layer, the second layer including at least one of a titanium layer and a nickel layer, and
• depositing a solderable layer on the second layer, the solderable layer selected from a group consisting of silver, gold, and tin;
• soldering the metallic bonding layer to a support structure;
• and
• connecting the electrical contacts to electrical inputs that supply the electrical current to the light-emissive region.

A method for fabricating a light-emitting element, the method comprising:

• depositing semiconducting layers on a front side of an electrically insulating substrate such that the semiconducting layers define a light-emissive region that emits light responsive to an electrical current flowing therethrough;
• forming electrical contacts contacting selected semiconducting layers;
• depositing a metallic bonding layer on a back side of the substrate, the depositing of a metallic bonding layer including:
• depositing an aluminum layer on the substrate,
• depositing a second layer on the aluminum layer, the second layer including at least one of a platinum layer and a nickel layer, and
• depositing a solderable layer on the second layer, the solderable layer selected from a group consisting of silver, gold, and tin;
• soldering the metallic bonding layer to a support structure;
• and
• connecting the electrical contacts to electrical inputs that supply the electrical current to the light-emissive region.

A method for fabricating a light-emitting element, the method comprising:

• depositing semiconducting layers on a front side of an electrically insulating substrate wafer such that the semiconducting layers define a light-emissive region that emits light responsive to an electrical current flowing therethrough;
• forming electrical contacts contacting selected semiconducting layers;
• depositing a metallic bonding layer on a back side of the substrate;
• soldering the metallic bonding layer to a support structure;
• connecting the electrical contacts to electrical inputs that supply the electrical current to the light-emissive region;
• prior to the depositing of the metallic bonding layer, thinning the back side of the substrate wafer to a selected reduced thickness;
• and
• subsequent to the depositing of the metallic bonding layer, dicing the substrate wafer to produce LED chips that are individually processed in the soldering and connecting steps.

A light emitting element comprising:

• a substrate selected from a group consisting of a sapphire substrate, a GaN substrate, and a SiC substrate;
• semiconducting layers disposed on a front side of the substrate defining a light-emissive region that emits light responsive to an electrical current flowing therethrough;
• electrical contacts contacting selected semiconducting layers;
• a metallic bonding layer on a back side of the substrate, the metallic bonding layer including:
• a first layer disposed on the substrate, the first layer including at least one of a silver layer and an aluminum layer,
• a second layer disposed on the first layer, the second layer including at least one of a titanium layer, a platinum layer, a nickel layer, a silver layer, an aluminum layer, and a rhodium layer;
• and
• a solderable layer disposed on the second layer, the solderable layer selected from a group consisting of silver, gold, and tin;
• and
• a solder bond securing the metallic bonding layer to an associated support structure.