Planar, Nonpolar M-Plane III-Nitride Films Grown on Miscut Substrates

Brief Description

A method for growing planar nonpolar III-nitride films that have atomically smooth surfaces without any macroscopic surface undulations. 

Background

The usefulness of gallium nitride (GaN) and its ternary and quaternary compounds incorporating aluminum and indium has been well established for fabrication of visible and ultraviolet optoelectronic devices and high-power electronic devices. Current nitride technology for these devices uses nitride films grown along the polar c-direction; however, these devices suffer from the quantum-confined Stark effect (QCSE). One way to combat the issue is to grow films on nonpolar planes of GaN in order to reduce polarization effects and the resulting decreases in device performance. While many films grown along a nonpolar direction have seen improved device performance, macroscopic surface undulations typically exist on their surfaces, which is harmful to successive film growth.   

Description

Researchers at UC Santa Barbara have created a method for growing planar nonpolar III-nitride films that have atomically smooth surfaces without any macroscopic surface undulations. This is achieved by selecting a miscut angle of substrate upon which the nonpolar III-nitride films are grown in order to suppress the surface undulations of the films. Without macroscopic surface undulations, films provide better device layers, templates, or substrates for device growth. The invention is relevant to all nonpolar planar films of nitrides, regardless of whether they are homoepitaxial or heteroepitaxial. 

Advantages

• Ability to control the crystal miscut direction and angle, leading to extra smooth surfaces and high quality device structures
• Enhanced step-flow growth mode via a miscut substrate suppresses defect formation and propagation
• Growth window of m-plane GaN is enlarged, leading to higher yield in manufacturing 

Applications

• LEDs
• Laser diodes (LDs)

Patent Status