Nitride underlayer and fabrication method thereof
A nitride underlayer structure includes a sputtered AlN buffer layer with open band-shaped holes, thus providing a stress release path before the nitride film is grown over the buffer layer. A light-emitting diode with such nitride underlayer structure has improved lattice quality of the nitride underlayer structure and the problem of surface cracks is resolved. A fabrication method of the nitride underlayer includes providing a substrate and forming a band-shaped material layer over the substrate; sputtering an AlN material layer over the band-shaped material layer and the substrate to form a flat film; scanning back and forth from the substrate end with a laser beam to decompose the band-shaped material layer to form a sputtered AlN buffer layer with flat surface and band-shaped holes inside; and forming an Al x In 1-x-y Ga y N layer (0≤x≤1, 0≤y≤1) over the sputtered AlN buffer layer.
1. A nitride underlayer comprising, from bottom up:
a substrate;
a sputtered AlN buffer layer; and
an Al X In 1-X-Y Ga Y N layer (0≤X≤1, 0≤Y≤1) grown via MOCVD,
wherein the sputtered AlN buffer layer has a flat surface and band-shaped holes therein formed with laser scanning and configured to provide a stress release path to release stress during growth of the Al X In 1-X-Y Ga Y N layer, and
wherein side walls of the holes and the AlN buffer layer are connected.
2. The nitride underlayer of claim 1 , wherein a thickness of the sputtered AlN layer is less than 1 μm.
3. The nitride underlayer of claim 1 , wherein the holes have a height of 0.01-0.5 μm.
4. The nitride underlayer of claim 1 , wherein the holes have a width of 100-500 μm.
5. A light-emitting diode, comprising, from bottom up:
a substrate;
a sputtered AlN buffer layer;
an Al X In 1-X-Y Ga Y N layer (0≤X≤1, 0≤Y≤1) grown via MOCVD,
wherein the sputtered AlN buffer layer has a flat surface and band-shaped holes therein formed with laser scanning and configured to provide a stress release path to release stress during growth of the Al X In 1-X-Y Ga Y N layer, and
wherein side walls of the holes and the AlN buffer layer are connected;
an n-type semiconductor layer;
an active layer; and
a p-type semiconductor layer.
6. The light-emitting diode of claim 5 , wherein a light-emitting wavelength of the light-emitting diode is 365 nm-210 nm.
7. The light-emitting diode of claim 5 , wherein a thickness of the sputtered AlN layer is less than 1 μm.
8. The light-emitting diode of claim 5 , wherein the holes have a width of 100-500 μm.
9. The light-emitting diode of claim 5 , wherein the holes have a height of 0.01-0.5 μm.