GaN LED TECHNOLOGY
White light from GaN LED's could become competitive with incandescent light sources in many general
lighting applications, such as automobile lighting. ("Let There be Light", IEEE Spectrum, September, 2002.)
Limitations to their commercialization are their efficiency and cost. Limitations on efficiency are associated
with the need for deposition of the GaN on sapphire or silicon carbide, which limits the depth and flawlessness
of the GaN layers. Flawless bulk GaN would work perfectly but is not available. The production techniques in
use today are metalorganic chemical vapor deposition (MOCVD) and molecular beam epitaxy (MBE). Under
development are techniques using solid-target PLD (Pulsed Laser Deposition). MOCVD and MBE are limited
to the use of sapphire and silicon carbide substrates at high temperature, solid target PLD can lead to target
deterioration and large particulate splashing over the growing film. Liquid-target pulsed laser deposition
eliminates splashing, but is still limited by small deposition areas dependent on the spot size of the laser.
The Large Volume Plasma Processor, (Eastlund, B., U. S. Patent 5,630,880, May 20, 1997 creates a high
plasma density with a temperature of 100 to 300 Ev that can ionize pellets of various materials and deposit
them on substrates located in adjacent chambers, connected by magnetic conduits.
A desk sized LVPP could produce ionized pellet material in large area beams and deposit 0.005 to 50
monolayers of each pellet. Sequential pellets could be of different materials. The system could deposition 60
different layers per second.
lighting applications, such as automobile lighting. ("Let There be Light", IEEE Spectrum, September, 2002.)
Limitations to their commercialization are their efficiency and cost. Limitations on efficiency are associated
with the need for deposition of the GaN on sapphire or silicon carbide, which limits the depth and flawlessness
of the GaN layers. Flawless bulk GaN would work perfectly but is not available. The production techniques in
use today are metalorganic chemical vapor deposition (MOCVD) and molecular beam epitaxy (MBE). Under
development are techniques using solid-target PLD (Pulsed Laser Deposition). MOCVD and MBE are limited
to the use of sapphire and silicon carbide substrates at high temperature, solid target PLD can lead to target
deterioration and large particulate splashing over the growing film. Liquid-target pulsed laser deposition
eliminates splashing, but is still limited by small deposition areas dependent on the spot size of the laser.
The Large Volume Plasma Processor, (Eastlund, B., U. S. Patent 5,630,880, May 20, 1997 creates a high
plasma density with a temperature of 100 to 300 Ev that can ionize pellets of various materials and deposit
them on substrates located in adjacent chambers, connected by magnetic conduits.
A desk sized LVPP could produce ionized pellet material in large area beams and deposit 0.005 to 50
monolayers of each pellet. Sequential pellets could be of different materials. The system could deposition 60
different layers per second.
LVPP PULSED PLASMAS