Method for growing semipolar nitride
A method for growing a semipolar nitride comprises steps: forming a plurality of parallel discrete trenches on a silicon substrate, each discrete trenches having a first wall and a second wall, wherein a tilt angle is formed between the surface of the silicon substrate and the first wall; forming a buffer layer on the silicon substrate and the trenches, wherein the buffer layer on the first wall has a plurality of growing zones and a plurality of non-growing zones among the growing zones and complementary to the growing zones; forming a cover layer on the buffer layer and revealing the growing zones; and growing a semipolar nitride from the growing zones of the buffer layer and covering the cover layer. Thereby cracks caused by thermal stress between the silicon substrate and semipolar nitride are decreased and the quality of the semipolar nitride film is improved.
1. A method for growing a semipolar nitride, comprising steps:
forming a plurality of trenches on a silicon substrate, each trench having a first wall and a second wall, wherein a tilt angle is formed between the surface of the silicon substrate and the first wall;
forming a buffer layer on the silicon substrate and the trenches, wherein the buffer layer on the first wall has a plurality of growing zones and a plurality of non-growing zones among the growing zones and complementary to the growing zones;
forming a cover layer on the buffer layer, the cover layer covering the non-growing zones but revealing the growing zones; and
growing a semipolar nitride from the growing zones of the buffer layer such that the semipolar nitride overlay the cover layer.
2. The method for growing a semipolar nitride according to claim 1 , wherein the angle between a surface of the silicon substrate and a (001) crystallographic plane of the silicon substrate ranges from 5 degrees to 10 degrees.
3. The method for growing a semipolar nitride according to claim 1 , wherein the first wall is a (111) crystallographic plane of the silicon substrate.
4. The method for growing a semipolar nitride according to claim 1 , wherein the second wall is a (−1-11) crystallographic plane of the silicon substrate.
5. The method for growing a semipolar nitride according to claim 1 , wherein each said trench further comprises a base joined to the first wall and the second wall.
6. The method for growing a semipolar nitride according to claim 1 , wherein each of the buffer layer and the semipolar nitride is made of a material selected from a group consisting of gallium nitride, aluminum nitride and indium nitride.
7. The method for growing a semipolar nitride according to claim 1 , wherein the semipolar nitride is grown with a MBE (Molecular Beam Epitaxy) method, an MOCVD (MOCVD (Metal Organic Chemical Vapor Deposition) method, or a chloride VPE (Vapor Phase Epitaxy) method.
8. The method for growing a semipolar nitride according to claim 1 , wherein the buffer layer has a thickness within a range from 0.5 nm to a depth of the trenches.
9. The method for growing a semipolar nitride according to claim 1 , wherein the buffer layer is grown with a MBE (Molecular Beam Epitaxy) method, an MOCVD (MOCVD (Metal Organic Chemical Vapor Deposition) method, or a chloride VPE (Vapor Phase Epitaxy) method.
10. The method for growing a semipolar nitride according to claim 1 , wherein the cover layer is made of silicon dioxide or silicon nitride.