Semiconductor light-emitting device and method of forming electrode
A semiconductor light-emitting device having an electrode that can be manufactured by a simple method and is unlikely to deteriorate, and a method for forming the electrode are provided. The semiconductor light-emitting device according to the present invention has a semiconductor layered structure having a light-emitting layer that emits light by supplying electric power and an electrode formed on the semiconductor layered structure. The electrode has a reflection layer that reflects light exiting from the light-emitting layer, a barrier layer formed on the upper side and side surface of the reflection layer, and a pad layer formed only on the top surface of the barrier layer.
1. A method for forming an electrode comprising:
a photolithography step of forming an overhang-shaped resist on a semiconductor layered structure having a light-emitting layer that emits light by supplying electric power;
a reflection layer forming step of forming a reflection layer on a surface on which the resist is formed;
a barrier layer forming step of forming a barrier layer posterior to the reflection layer forming step;
a pad layer forming step of forming a pad layer posterior to the barrier layer forming step; and
a lift-off step of removing the resist posterior to the pad layer forming step, wherein
a side surface coverage, that is a value obtained by dividing a side deposition rate by a deposition rate vertical to a substrate
is 15% or more at the start point of the barrier layer forming step and is 0% at an end point of the barrier layer forming step and in the pad layer forming step.
2. The method according to claim 1 , wherein
the reflection layer, the barrier layer and the pad layer are formed in the reflection layer forming step, the barrier layer forming step and the pad layer forming step, respectively, by continuous layer deposition.
3. The method according to claim 1 , wherein
the barrier layer at the end point of the barrier layer deposition step has a film thickness of 200 nm or more.
4. The method according to claim 1 , further comprising
an adhesion layer forming step of forming an adhesion layer that contacts with a top surface of the semiconductor layered structure, between the photolithography step and the reflection layer forming step, wherein
a film deposition rate of the adhesion layer in the adhesion layer forming step is more than 0 nm/sec and 0.05 nm/sec or less.