Micro light emitting diode
Embodiments generally relate to micro-device arrays. In some embodiments, an array comprises a substrate and a plurality of micro-devices. Each micro-device is suspended over a cavity in the substrate by at least one lateral hinge attached to a side post formed into the substrate. Each micro-device comprises a bonding layer; a metal contact; semiconductor device layers; and a buffer layer. The semiconductor device layers may comprise GaN-based LED layers; wherein the buffer layer comprises AlGaN; and wherein the substrate comprises (111) oriented Silicon. In other cases, the semiconductor device layers may comprise InGaAsP-based LED layers; wherein the buffer layer comprises InGaP; and wherein the substrate comprises GaAs.
1. An array comprising:
a substrate; and
a plurality of micro-devices;
wherein each micro-device is suspended over a cavity in the substrate by at least one lateral hinge attached to a side post formed into the substrate; and
wherein each micro-device comprises:
a bonding layer;
a metal contact;
semiconductor device layers; and
a buffer layer.
2. The array of claim 1 ,
wherein the semiconductor device layers comprise GaN-based LED layers;
wherein the buffer layer comprises AlGaN; and
wherein the substrate comprises (111) oriented Silicon.
3. The array of claim 1 ,
wherein the semiconductor device layers comprise InGaAsP-based LED layers;
wherein the buffer layer comprises InGaP; and
wherein the substrate comprises GaAs.
4. The array of claim 1 ,
wherein the semiconductor device layers comprise CMOS layers;
wherein the buffer layer comprises SiO2; and
wherein the substrate comprises (100) oriented Silicon.
5. The array of claim 1 ,
wherein the side posts are positioned between adjacent micro-devices.
6. The array of claim 1 ,
wherein the cross-section shape of each side post is one of round, square and rectangular.
7. The array of claim 1 ,
wherein one of the side posts is shaped as a long wall positioned between two rows of micro-devices.
8. The array of claim 1 ,
wherein side posts of different cross-section shapes are present in the array.
9. The array of claim 1 ,
wherein the bonding layer consists of either one metal or a metal stack; and
wherein the bonding layer has a melting temperature below 500 C.
10. The array of claim 1 ,
wherein the bonding layer is configured to form solder balls after melting.
11. The array of claim 1 ,
wherein each lateral hinge is configured to be broken if and when a micro-device attached to that hinge is forcibly pushed towards the substrate.
12. The array of claim 1 ,
wherein the substrate is an epitaxial substrate.
13. The array of claim 2 ,
wherein the metal contact is optically reflective, with a reflectivity greater than 70%.
14. The array of claim 3 ,
wherein the metal contact is optically reflective, with a reflectivity greater than 70%.