Large GaN single-crystal substrates with low dislocation density are the key materials for the commercial production of GaN-based laser diodes. We developed a new method to reduce the dislocations, named dislocation elimination by the epitaxial-growth with inverse-pyramidal pits (DEEP). A thick GaN film is epitaxially grown on a GaAs substrate with hydride vapor-phase epitaxy and then is separated from the GaAs substrate. The thick GaN layer grows with numerous large inverse-pyramidal pits. As the growth proceeds, dislocations in the GaN film are concentrated to the center of the pit and a wide area with low dislocation density is formed within the pit except the center area. To control the dislocation artificially, the position of the pits is fixed at a predetermined position by means of the selective growth of different polarity GaN film. This process was named as advanced DEEP (A-DEEP).GaN substrates with the A-DEEP method satisfied all the requirements for the violet laser diodes. We continued to develop new GaN substrates such as large-diameter c-plane substrates as well as nonpolar/semipolar GaN substrates. In particular, we overcame the green gap problem and developed the world's first true green laser diodes by selecting an optimal crystal plane.
If you need more information about GaN Substrate Technologies for Optical Devices, please visit:http://www.qualitymaterial.net or send us email at firstname.lastname@example.org.
Post a Comment