Method of forming a non-polar/semi-polar semiconductor template layer on unevenly patterned substrate
View Patent ↗Provided are a high-quality non-polar/semi-polar semiconductor device with reduced defect density and improved internal quantum efficiency and light extraction efficiency, and a manufacturing method thereof. The manufacturing method is a method for manufacturing a semiconductor device, in which a template layer and a semiconductor device structure are formed on a sapphire substrate having a crystal plane for growing a non-polar or semi-polar nitride semiconductor layer. The sapphire substrate is etched to form uneven patterns, and the template layer including a nitride semiconductor layer and a GaN layer is formed on the sapphire substrate in which the uneven patterns are formed.
1. A method for manufacturing a semiconductor device, the method comprising:
etching a sapphire substrate to form uneven patterns thereon, the sapphire substrate comprising an A-plane or M-plane crystal plane; and
forming a template layer on the etched sapphire substrate,
wherein forming the template layer comprises:
forming a low-temperature nitride semiconductor layer at a temperature in the range of 400 to 700° C.;
forming a high-temperature nitride semiconductor layer at a temperature in the range of 700 to 1100° C.; and
forming an undoped GaN layer at a temperature in the range of 800 to 1100° C., and
wherein the low-temperature nitride semiconductor layer of the template layer contacts the sapphire substrate.
2. The method of claim 1 , wherein the low-temperature nitride semiconductor layer and the high-temperature nitride semiconductor layer each comprise In x Al y Ga 1-x-y N (0≦x≦1, 0≦y≦1, 0≦x+y≦1).
3. The method of claim 1 , wherein etching the sapphire substrate to form uneven patterns comprises:
forming photoresist patterns corresponding to the uneven patterns on the sapphire substrate; and
etching the photoresist patterns using an anisotropic etching process comprising inductively coupled plasma etching.
4. The method of claim 1 , wherein etching the sapphire substrate to form uneven patterns comprises:
forming photoresist patterns corresponding to the uneven patterns on the sapphire substrate; and
etching the photoresist patterns using an isotropic etching process using an acid solution or an alkali solution.
5. The method of claim 1 , wherein the uneven patterns comprise a polygonal shape, a circular shape, a semicircular shape, a triangular shape, or a rectangular shape.
6. The method of claim 1 , wherein an array of the uneven patterns is formed so that each uneven pattern comprises a width of 10 nanometers to 100 micrometers and a height of 10 nanometers to 100 micrometers, and an interval between each uneven pattern is 10 nanometers to 100 micrometers.
7. The method of claim 1 , further comprising:
forming a light-emitting diode (LED) layer on the template layer,
wherein forming the LED layer comprises growing an n-type nitride semiconductor layer on the template layer, growing at least one active layer on the n-type nitride semiconductor layer, and growing a p-type nitride semiconductor layer on the at least one active layer.
8. The method of claim 1 , further comprising:
coating a photoresist on the sapphire substrate before etching the sapphire substrate; and
exposing the photoresist using a photo mask comprising a pattern array,
wherein etching the sapphire substrate is performed using the exposed photoresist.
9. The method of claim 1 , wherein the template layer comprises a non-polar or semi-polar nitride semiconductor layer.
10. The method of claim 1 , wherein the thickness of each of the low-temperature nitride semiconductor layer, the high-temperature nitride semiconductor layer, and the undoped GaN layer is in the range of 10 to 20,000 Å.