Electrochemical etching strategy for shaping monolithic 3D structures from 4H-SiC wafers

Area of Science:

• Materials Science
• Semiconductor Physics
• Nanotechnology

Background:

• Silicon Carbide (SiC) is a versatile material with applications in electronics, quantum technologies, nano-mechanics, and photonics.
• Conventional methods for 3D SiC structuring, such as dry etching, have limitations.
• SiC's inertness to wet etching necessitates alternative fabrication strategies.

Purpose of the Study:

• To introduce a novel electrochemical etching strategy for fabricating 3D structures in Silicon Carbide.
• To leverage selective doping for defining etchable regions and achieving high-resolution patterning.
• To demonstrate the fabrication of various micro- and nano-devices from single-crystal SiC wafers.

Main Methods:

• Developed an electrochemical etching process for Silicon Carbide.
• Utilized p-dopant implantation to define etchable volumes within the SiC wafer.
• Exploited the inertness of n-doped SiC regions to create sharp etching contrasts.

Main Results:

• Successfully fabricated monolithic cantilevers, disk-shaped optical resonators, and membranes from single-crystal SiC.
• Achieved high-quality surfaces with sharp etching contrasts between doped and undoped regions.
• Demonstrated enhanced surface quality and shape stability of fabricated devices after thermal treatment up to 1550°C.

Conclusions:

• The proposed electrochemical etching method offers a versatile and precise approach for 3D structuring of SiC.
• This technique enables the creation of high-performance, multi-functional SiC devices for advanced applications.
• The process is compatible with high-temperature treatments, further enhancing device stability and functionality.