Wednesday, December 15, 2010
【 Weak current College 】 LED vertical structure technical analysis 】
Summary: as the Sapphire substrates poor thermal conductivity, impact led luminous efficiency. In order to solve the thermal challenges LED, the future is likely to be mainly uses the vertical structure of the framework to promote LED LED industry in technology development. On the vertical structure of the LED technology I believe we all have heard the following from the technology described, would surface for reference.
Because Sapphire substrates poor thermal conductivity, impact led luminous efficiency. In order to address the challenges of the future LED, is likely to be mainly uses the vertical structure of the framework to promote LED LED industry in technology development. On the vertical structure of the LED technology I believe we all have heard the following from the technology described, would surface for reference.
We know that the LED chip has two basic structures, horizontal structure (Lateral) and vertical structure (Vertical). Transverse structure LED chips two electrodes on the same side of the LED chip, the current in the n-and p-type restriction in lateral flow of distance. Vertical structure of the LED chip in the two electrodes are epitaxial layer on both sides of the LED, because graphical electrodes and all of p-type restriction layer as the second electrode allows current to flow through to all almost vertically LED Epitaxial layers, rarely lateral flow of current, you can improve the surface structure of current distribution issues, improve the efficiency, you can solve the problem of shading P pole, LED light-emitting area enhancement.
Let's understand the vertical structure of the LED manufacturing technology and basic method:
Manufacturing vertical structure LED chip technology there are three main methods:
First, the use of silicon carbide substrate growing GaN films, the advantage is in the same operation current condition, lumen, long life, less than a silicon substrate will absorb light.
Second, the use of chip bonding and split technology manufacturing. Advantages of lumen, long life, less than is required to process the LED surface to enhance luminous efficiency.
3. is the use of different substrates such as silicon substrate grown Gan LED epitaxial layer, the advantage is the heat, and easy processing.
Manufacturing vertical structure LED chips there are two basic methods: split growth substrate and not split growth substrate. Which grows in the growth of gallium arsenide substrate on the vertical structure of the GaP Foundation LED chip has two structures:
Do not split a conductive substrate GaAs growth: growth in conductive GaAs substrate by upper deck stacked conductive DBR reflective layer, growth GaP Foundation LED Epitaxial layers in conductive DBR reflective layer.
Split the growth of gallium arsenide substrate: layer stacked reflector in the GaP Foundation LED epitaxial layer bonding conductive support substrate, split GaAs substrate. Conductive substrates including support, gallium arsenide substrate, gallium phosphide substrate, silicon substrate, metals and alloys, etc.
In addition, growth in the silicon chip in a vertical Gan LED also have two structures:
Do not split Silicon growth substrate: growth in conductive silicon substrate for upper-layer stacked metal reflectors or reflective layer of conductive DBR, growth of GaN-based led Epitaxial layers of conductive metal reflectors or DBR reflective layer.
Split Silicon growth substrate: layer stacked metal reflectors in GaN-based led epitaxial layer, in metal reflectors on bonding conductive support substrate, split Silicon growth substrate.
Simple instructions for manufacturing vertical GaN-based led process: layer stacked reflector in GaN-based led epitaxial layer on bond over a conductive substrate, split supported Sapphire growing substrate. Conductive substrates including support, metal and alloy substrate, silicon substrates, etc.
Both the GaP Foundation LED, Gan LED, LED the ZnO base class through-hole LED vertical structure, compared with traditional structure LED has a big advantage in:
1. at present, all existing vertical structure LED colors: Red LED, green LED, blue LED and UV LED can be made through-hole LED vertical structure have great application market.
2. all manufacturing processes are on the chip (wafer) level.
3, no golden line and external power phase connection, uses the vertical structure of through-hole LED chip package thickness reduction. Therefore, you can be used in the manufacture of ultra thin device, such as backlight, etc.