A partly-contacted epitaxial lateral overgrowth method applied to GaN material

Area of Science:

• Materials Science
• Crystal Growth
• Semiconductor Technology

Background:

• Epitaxial lateral overgrowth (ELO) is crucial for high-quality semiconductor layer fabrication.
• Traditional ELO methods often face challenges with tilt and dislocation formation in overgrowth layers.
• Achieving low-tilt, high-quality overgrowth is essential for advanced electronic and optoelectronic devices.

Purpose of the Study:

• To introduce and demonstrate a novel partly-contacted epitaxial lateral overgrowth (PC-ELO) method.
• To investigate the elimination of tilt in overgrowth stripes using the PC-ELO technique.
• To report an improved, lithography-free microsphere mask method for PC-ELO of Gallium Nitride (GaN).

Main Methods:

• Development of a partly-contacted ELO (PC-ELO) strategy where the overgrowth layer partially contacts the seed layer.
• Utilization of specialized mask structures, with and without lithography.
• Application of an improved monolayer microsphere mask method for lithography-free PC-ELO of GaN.

Main Results:

• Successful elimination of tilt angle in overgrowth stripes through contact with the seed layer.
• Achieved high-quality coalescence front with an average linear dislocation density below 6.4 × 10^3 cm^-1.
• XRD rocking curves showed no detectable peak splitting, confirming the absence of tilt; AFM revealed minimal surface discontinuities.

Conclusions:

• The PC-ELO method effectively eliminates tilt in overgrowth stripes, leading to improved crystal quality.
• The lithography-free microsphere mask approach is a viable and efficient technique for PC-ELO of GaN.
• This method offers a pathway to high-quality, low-misorientation semiconductor layers for advanced applications.