Method for producing group III nitride semiconductor light-emitting device

摘要

The present invention provides a Group III nitride semiconductor exhibiting reduced contact resistance. A first p-type contact layer of GaN doped with Mg is formed on a p-type cladding layer, using hydrogen as a carrier gas at a growth temperature of 850° C. to 1,050° C., so as to have a thickness of 10 nm to 300 nm. The Mg concentration is 1×1019/cm3 to 1×1020/cm3. Subsequently, a second p-type contact layer of GaN doped with Mg is formed, using nitrogen instead of hydrogen as a carrier gas at a temperature of 600° C. to 800° C. so as to have a thickness of two monolayers to 100 Å. The Mg concentration is 2×1020/cm3 to 1×1021/cm3.

主权项

1. A method for producing a Group III nitride semiconductor light-emitting device having a first p-type contact layer formed of GaN doped with Mg, and a second p-type contact layer formed of GaN doped with Mg at a concentration higher than that of the first p-type contact layer on the first p-type contact layer, the method comprising the steps of:
forming the first p-type contact layer of GaN with a thickness in a range from 10 nm to 300 nm and a Mg concentration in a range from 8×1019/cm3 to 1×1020/cm3 through MOCVD using ammonia (NH3) as a nitrogen source, trimethylgallium (TMG; Ga(CH3)3) as a Ga source, bis(cyclopentadienyl)magnesium (Cp2Mg; Mg(C5H5)2) as a p-type doping gas and hydrogen as a carrier gas at a temperature of 850° C. to 1,050° C.; stopping supplies of the trimethylgallium, the bis(cyclopentadienyl)magnesium, and the hydrogen after a completion of the forming of the first p-type contact layer and keeping a flow rate of the ammonia at the same value as in the forming of the first p-type contact layer; lowering a temperature to a growth temperature for the second p-type contact layer in an ammonia atmosphere after the completion of the forming of the first p-type contact layer and before starting to form the second p-type contact layer; starting supplies of nitrogen as a carrier gas, the trimethylgallium, and the bis(cyclopentadienyl)magnesium; forming the second p-type contact layer with a thickness in a range from two monolayers to 50 Å and a Mg concentration in a range from 5×1020/cm3 to 1×1021/cm3 through MOCVD using the nitrogen as the carrier gas at a temperature of 600° C. to 800° C. on the first p-type contact layer after the forming of the first p-type contact layer; forming a transparent electrode on the second p-type contact layer; wherein the second p-type contact layer is formed at a growth rate of 0.03 times to 0.1 times the growth rate of the first p-type contact layer by decreasing a flow rate of the trimethylgallium for the forming of the second p-type contact layer lower than a flow rate of the trimethylgallium for the forming of the first p-type contact layer.