Two-dimensional buffer breaks substrate limit in III-nitrides epitaxy.

Area of Science:

• Materials Science
• Semiconductor Physics
• Nanotechnology

Background:

• Heterointegration of electronic and optoelectronic devices requires diverse substrate materials for single-crystalline film growth.
• Current methods are limited to substrates with matched crystalline lattices, restricting the use of non-single-crystalline materials.
• Amorphous silicon dioxide (SiO2) is an attractive, low-cost substrate but lacks a suitable crystalline structure for conventional epitaxy.

Purpose of the Study:

• To develop an epitaxy strategy for wafer-scale growth of high-quality single-crystalline gallium nitride (GaN) on amorphous silicon dioxide (SiO2) substrates.
• To overcome the lattice-matching limitations in semiconductor heterointegration.
• To enable the use of non-single-crystalline substrates for advanced electronic and optoelectronic devices.

Main Methods:

• A novel epitaxy strategy involving a chemical bond transition was employed.
• Multilayer molybdenum disulfide (MoS2) was converted to molybdenum nitride (MoN) to serve as a buffer layer.
• The MoN buffer layer engineered a preferred orientation for subsequent GaN epitaxy.

Main Results:

• High-quality single-crystalline GaN was successfully grown on an amorphous SiO2 substrate.
• An AlGaN/AlN/GaN heterostructure was fabricated with high electron mobility (>2000 cm²/Vs).
• Resultant high-electron-mobility transistors demonstrated performance comparable to commercial devices.

Conclusions:

• The developed epitaxy strategy enables the growth of single-crystalline GaN on amorphous substrates, expanding material choices for semiconductor manufacturing.
• This approach facilitates the heterointegration of advanced electronic and optoelectronic devices.
• The method holds potential for cost-effective production of high-performance semiconductor devices.