E.O. Lawrence Berkeley National Laboratory

APPLICATION OF TECHNOLOGY:

• Flat panel displays
• Energy efficient lighting
• Field effect transistors (FETs)
• Blue and green light semiconductor lasers
• Blue and green light emitting diodes (LEDs)

ADVANTAGES:

• Improved electrical and structural properties of epitaxial GaN thin films
• Procedure can be used with any lattice mismatched substrate that is wetted by the new metallic liquid Ga buffer
• Use of Ga buffer expected to be beneficial for any III-N thin film growth process

ABSTRACT:

Eicke Weber and colleagues at Berkeley Lab has made advances in controlling the quality of GaN thin films. A buffer layer of metallic liquid Ga has been optimized to allow growth of high quality epitaxial GaN thin films on lattice mismatched substrates, such as sapphire. Berkeley Lab’s new buffer improves the electrical and structural properties of the films. The new, metallic, liquid gallium buffer can also be transferred to the growth of high quality GaN films on any lattice mismatched substrate that is wetted by the new buffer. This innovation will help remove a major obstacle in GaN device technology—that of integrating it to the current, well-developed device technology. In addition, because a metallic gallium buffer layer generally provides favorable two-dimensional nucleation conditions for the subsequent growth of the GaN main layer at higher growth temperatures—1000K or less for Molecular Beam Epitaxy (MBE) and 1300K for Metal Organic Chemical Vapor Deposition (MOCVD)—use of a metallic Ga buffer layer is expected to be beneficial for any III-N thin film growth process.

STATUS: U.S. Patent #6,563,144. Available for licensing

FOR MORE INFORMATION PLEASE SEE:

• Kruger J,m Kim Y., Subramanya S., Weber E., "Towards the Development of Defect-Free GaN Substrates: Defect Control in Hetero-Epitaxially Grown GaN by New Buffer Layer Design".

REFERENCE NUMBER: IB-1461

SEE THESE OTHER BERKELEY LAB TECHNOLOGIES IN THIS FIELD:

• Growth of GaN with a Low Density of Structural Defects, IB-1619
• High Quality GaN Films on Silicon Substrates Using HfN Buffer Layers, IB-1800
• Improved GaN MBE-Growth using Bismuth as a Surfactant, IB-1290