Chapter 4
Epitaxial of III-Nitride LED Materials
III-nitrides include GaN, InN, AlN and their ternary and quaternary solid solutions. Since they are all direct band gap semiconductors, they are particularly suitable for fabricating light-emitting devices. However, the bulk single crystal growth
conditions of the nitride material are complicated and require high temperature and
high pressure. The current nitride material is mainly prepared by heteroepitaxial
on other substrates. In 1986, Hiroshi Amano and Akasaki used MOCVD epitaxial
low-temperature AlN buffer layer to successfully grow GaN films with good surface
structure and good crystal quality. This work laid the foundation for the subsequent
growth of nitride LED epitaxial materials. In addition to the MOCVD, LPE, MBE,
HVPE, etc. can also be used to prepare nitride LEDs.
GaN-based white LEDs have great advantages compared with traditional illumination sources in terms of energy saving, environmental protection, etc. They are a
new generation of illumination sources with broad market prospects. The white LEDs
that use blue-chips to emit phosphors are the current mainstream technology. The
preparation process can be divided into several parts such as substrate material preparation, material epitaxial, chip fabrication and packaging. The most critical process
step is the epitaxial growth of materials. The material epitaxial process determines
the basic performance of the LED such as wavelength, voltage, internal quantum
efficiency and output power.
4.1 Basic Models of Epitaxial
According to its growth mode, the film can be divided into the following three types
© Science Press and Springer Nature Singapore Pte Ltd. 2020
J. Li et al., III-Nitrides Light Emitting Diodes: Technology and Applications,
Springer Series in Materials Science 306,
https://doi.org/10.1007/978-981-15-7949-3_4
33
Epitaxial of III-Nitride LED Materials
III-nitrides include GaN, InN, AlN and their ternary and quaternary solid solutions. Since they are all direct band gap semiconductors, they are particularly suitable for fabricating light-emitting devices. However, the bulk single crystal growth
conditions of the nitride material are complicated and require high temperature and
high pressure. The current nitride material is mainly prepared by heteroepitaxial
on other substrates. In 1986, Hiroshi Amano and Akasaki used MOCVD epitaxial
low-temperature AlN buffer layer to successfully grow GaN films with good surface
structure and good crystal quality. This work laid the foundation for the subsequent
growth of nitride LED epitaxial materials. In addition to the MOCVD, LPE, MBE,
HVPE, etc. can also be used to prepare nitride LEDs.
GaN-based white LEDs have great advantages compared with traditional illumination sources in terms of energy saving, environmental protection, etc. They are a
new generation of illumination sources with broad market prospects. The white LEDs
that use blue-chips to emit phosphors are the current mainstream technology. The
preparation process can be divided into several parts such as substrate material preparation, material epitaxial, chip fabrication and packaging. The most critical process
step is the epitaxial growth of materials. The material epitaxial process determines
the basic performance of the LED such as wavelength, voltage, internal quantum
efficiency and output power.
4.1 Basic Models of Epitaxial
According to its growth mode, the film can be divided into the following three types
© Science Press and Springer Nature Singapore Pte Ltd. 2020
J. Li et al., III-Nitrides Light Emitting Diodes: Technology and Applications,
Springer Series in Materials Science 306,
https://doi.org/10.1007/978-981-15-7949-3_4
33