Semiconductor device having a light emitting element
View Patent ↗An InGaN active layer is formed on a sapphire substrate. A p-side electrode is formed on the InGaN active layer to supply an electric current to this InGaN active layer. The p-side electrode includes {circle around (1)} an Ni layer for forming an ohmic contact with a p-GaN layer, {circle around (2)} an Mo layer having a barrier function of preventing diffusion of impurities, {circle around (3)} an Al layer as a high-reflection electrode, {circle around (4)} a Ti layer having a barrier function, and {circle around (5)} an Au layer for improving the contact with a submount on a lead frame. The p-side electrode having this five-layered structure realizes an ohmic contact and high reflectance at the same time.
1. A semiconductor device comprising:
a lead frame;
a submount on said lead frame;
a light emitting element on said submount; and
a resin covering said light emitting element,
said light emitting element comprising:
a substrate;
a light emitting layer formed on said substrate to emit light, wherein said light emitting layer includes a first semiconductor layer of a first conductivity type, an active layer formed on said first semiconductor layer to emit the light and a second semiconductor layer of a second conductivity type formed on said active layer;
a first electrode contacting said second semiconductor layer; and
a second electrode contacting said first semiconductor layer,
said first electrode comprising:
an ohmic layer in ohmic contact with said second semiconductor layer;
a first barrier layer formed on said ohmic layer;
a light reflecting layer formed on said first barrier layer and comprising a metal including Ag;
a second barrier layer formed on said light reflecting layer; and
an overcoat electrode for mounting formed on said second barrier layer,
wherein said first barrier layer comprises a material different from that of said ohmic layer and said light reflecting layer comprises a material different from that of said overcoat electrode.
2. The light emitting element according to claim 1 ,
wherein said substrate is an insulating substrate.
3. The light emitting element according to claim 2 ,
wherein said substrate is made of a sapphire.
4. The light emitting element according to claim 1 ,
wherein said first electrode is located at a place which is above the center of said substrate.
5. The light emitting element according to claim 4 ,
wherein said second electrode is located at a place which surrounds said first electrode.
6. A semiconductor device comprising:
a lead frame;
a submount on said lead frame;
a light emitting element on said submount; and
a resin covering said light emitting element,
said light emitting element comprising:
a substrate;
a light emitting layer formed on said substrate to emit light, wherein said light emitting layer includes a first semiconductor layer of a first conductivity type, an active layer formed on said first semiconductor layer to emit the light and a second semiconductor layer of a second conductivity type formed on said active layer;
a first electrode contacting said second semiconductor layer; and
a second electrode contacting said first semiconductor layer,
said first electrode comprising:
an ohmic layer in ohmic contact with said second semiconductor layer and comprising a metal including Pt;
a first barrier layer formed on said ohmic layer, comprising a metal including Pt;
a light reflecting layer formed on said first barrier layer;
a second barrier layer formed on said light reflecting layer; and
an overcoat electrode for mounting formed on said second barrier layer,
wherein said first barrier layer comprises a material different from that of said ohmic layer and said light reflecting layer comprises a material different from that of said overcoat electrode.
7. The light emitting element according to claim 6 ,
wherein said substrate is an insulating substrate.
8. The light emitting element according to claim 7 ,
wherein said substrate is made of a sapphire.
9. The light emitting element according to claim 6 ,
wherein said first electrode is located at a place which is above the center of said substrate.
10. The light emitting element according to claim 9 ,
wherein said second electrode is located at a place which surrounds said first electrode.
11. A semiconductor device comprising:
a lead frame;
a submount on said lead frame;
a light emitting element on said submount; and
a resin covering said light emitting element,
said light emitting element comprising:
a substrate;
a light emitting layer formed on said substrate to emit light, wherein said light emitting layer includes a first semiconductor layer of a first conductivity type, an active layer formed on said first semiconductor layer to emit the light and a second semiconductor layer of a second conductivity type formed on said active layer;
a first electrode contacting said second semiconductor layer; and
a second electrode contacting said substrate,
said first electrode comprising:
an ohmic layer in ohmic contact with said second semiconductor layer;
a first barrier layer formed on said ohmic layer;
a light reflecting layer formed on said first barrier layer and comprising a metal including Ag;
a second barrier layer formed on said light reflecting layer; and
an overcoat electrode for mounting formed on said second barrier layer,
wherein said first barrier layer comprises a material different from that of said ohmic layer and said light reflecting layer comprises a material different from that of said overcoat electrode.
12. The light emitting element according to claim 11 ,
wherein said substrate is a conductive substrate.
13. The light emitting element according to claim 12 ,
wherein said substrate includes Ga.
14. The light emitting element according to claim 11 ,
wherein said first electrode is located at a place which is above the center of said substrate.
15. The light emitting element according to claim 14 ,
wherein said second electrode is located at a place which surrounds said first electrode.
16. A semiconductor device comprising:
a lead frame;
a submount on said lead frame;
a light emitting element on said submount; and
a resin covering said light emitting element,
said light emitting element comprising:
a substrate;
a light emitting layer formed on said substrate to emit light, wherein said light emitting layer includes a first semiconductor layer of a first conductivity type, an active layer formed on said first semiconductor layer to emit the light and a second semiconductor layer of a second conductivity type formed on said active layer;
a first electrode contacting said second semiconductor layer; and
a second electrode contacting said substrate,
said first electrode comprising:
an ohmic layer in ohmic contact with said second semiconductor layer and comprising a metal including Pt;
a first barrier layer formed on said ohmic layer, comprising a metal including Pt;
a light reflecting layer formed on said first barrier layer;
a second barrier layer formed on said light reflecting layer; and
an overcoat electrode for mounting formed on said second barrier layer,
wherein said first barrier layer comprises a material different from that of said ohmic layer and said light reflecting layer comprises a material different from that of said overcoat electrode.
17. The light emitting element according to claim 16 ,
wherein said substrate is a conductive substrate.
18. The light emitting element according to claim 17 ,
wherein said substrate includes Ga.
19. The light emitting element according to claim 6 ,
wherein said first electrode is located at a place which is above the center of said substrate.
20. The light emitting element according to claim 19 ,
wherein said second electrode is located at a place which surrounds said first electrode.