Study of thick microporous silicon layer from highly resistive silicon

Area of Science:

• Materials Science
• Electrical Engineering
• Nanotechnology

Background:

• Porous silicon (PS) is a promising material for power electronics due to its electrical insulating properties.
• Smooth PS surfaces are essential for subsequent processing steps like photolithography and metallization.

Purpose of the Study:

• To develop a method for fabricating smooth porous silicon surfaces suitable for power electronic applications.
• To investigate the relationship between porosity, thickness, and structural integrity of microporous silicon.

Main Methods:

• Utilized low-doped (30-50 Ohmcm) p-type silicon.
• Employed a specific etching solution containing HF-H2O and acetic acid.
• Fabricated structures with pore dimensions ranging from nanometers (microporous) to micrometers (macroporous).

Main Results:

• Successfully implemented microporous silicon structures using the HF-H2O and acetic acid solution.
• Achieved layers up to 400 micrometers thick with a porosity of 50%.
• Demonstrated that porosity versus thickness is a key parameter for evaluating microporous silicon structure integrity.

Conclusions:

• The developed method enables the fabrication of smooth porous silicon suitable for power electronic device integration.
• Microporous silicon layers with controlled porosity and significant thickness can be achieved.
• Porosity and thickness are critical factors for ensuring the structural integrity of fabricated porous silicon layers.