Processing-Induced Electrically Active Defects in Black Silicon Nanowire Devices.

Area of Science:

• Materials Science
• Solid State Physics
• Nanotechnology

Background:

• Silicon nanowires (Si NWs) are crucial for energy devices, with black silicon (BSi)-NWs offering industrial advantages via deep reactive ion etching (RIE).
• RIE processing, while industrially relevant for microelectronics, may introduce detrimental deep states into the band gap of BSi-NWs, affecting their electrical properties.

Purpose of the Study:

• To identify electrically active deep levels and associated defects in dry-etched Si NW arrays using deep level transient spectroscopy (DLTS).
• To confirm the applicability of existing theoretical frameworks for deep level electronic behavior in low-dimensional Si NWs.

Main Methods:

• Application of deep level transient spectroscopy (DLTS) to analyze defects in black silicon (BSi)-NW arrays.
• Fabrication of Schottky barrier diodes using BSi-NWs for DLTS measurements.
• Analysis and fitting of DLTS spectra to characterize deep levels.

Main Results:

• Electrically active deep levels and associated defects were successfully identified in dry-etched Si NW arrays.
• DLTS spectra fitting confirmed that the theoretical framework for deep level electronic behavior is applicable to low-dimensional Si NWs.
• This validation holds for both simple point-like defects and more complex defect structures.

Conclusions:

• Deep reactive ion etching (RIE) introduces identifiable deep levels in black silicon (BSi)-nanowires (NWs).
• Deep level transient spectroscopy (DLTS) is effective for characterizing these defects in NWs, even in low-dimensional structures.
• The electronic behavior of deep levels in Si NWs aligns with established theories for bulk silicon, provided quantum confinement effects are absent.