1. Field of the Invention
The invention relates to an epitaxy base, a semiconductor light emitting device, and manufacturing methods thereof, and particularly relates to an epitaxy base, a semiconductor light emitting device, and manufacturing methods thereof offering a preferable epitaxy quality.
2. Description of Related Art
Semiconductor light emitting devices, such as light-emitting diodes (LEDs), are manufactured by using compounds (e.g. gallium nitride, gallium phosphide, and gallium arsenide.) containing a Group III-V element. A lifetime of the LEDs may be as long as 100,000 hours. In addition, the LEDs have the advantages of a quick responding speed (approximately 10−9 seconds), smaller size, lower power consumption, low pollution, high reliability, as well as the capability for mass production. Thus, LEDs are constantly used in a variety of fields, such as luminaire, traffic signal lamps, mobile phones, scanners, and fax machines.
During the manufacturing process of the semiconductor light emitting devices, due to the differences in lattice constant and thermal expansion coefficient (CTE) between semiconductor layers and a hetero-substrate, dislocations and a thermal stress caused by CTE mismatch in the epitaxy process are commonly found on the semiconductor layers. Therefore, the conventional semiconductor light emitting device may be severely bent due to the stress and the chance of generating cracks is thus increased.