Improved Anisotropic Strain Control in Semipolar Nitride Devices

Brief Description

A method to control the anisotrophy of strain in semipolar nitride-based active layers of optoelectronic devices while maintaining high device performance and efficiency.

Background

Nitride-based devices are typically grown coherently because dislocations can cause poor device performance. The presence of strain in quantum wells (QWs) can modulate the band structure of QWs (polarization of spontaneous emission and gain). Generally, strain in semipolar nitride epitaxial layers is anisotropic due to the different lattice parameters. This strain-anisotropy is automatically determined by the difference of lattice constant between a considered epitaxial layer and the substrate on which the considered layer is coherently grown. Therefore, techniques are needed to control the anisotropy of strain in QWs.

Description

UC Santa Barbara researchers have created a method to control the anisotrophy of strain in semipolar nitride-based active layers of optoelectronic devices while maintaining high device performance and efficiency. Using this method, misfit dislocations may be restricted to regions located far from device layers.

Advantages

• Controlled anistropic strain
• High efficiency
• Improved device performance
• Increased device yield
• Reduction of dislocations in active devices

Applications

• LEDs 
• Laser diodes (LDs)

Patent Status