Bottom-up nanoscale patterning and selective deposition on silicon nanowires

Area of Science:

• Materials Science
• Nanotechnology
• Semiconductor Physics

Background:

• Semiconductor nanowires are crucial for advanced electronics.
• Precise control over thin film deposition on nanowires is challenging.
• Existing methods lack the resolution for complex dopant-profile-aligned structures.

Purpose of the Study:

• To demonstrate a novel bottom-up process for programming coaxial thin film deposition on semiconductor nanowires.
• To align thin film deposition with the underlying dopant profile of nanowires.
• To enable the fabrication of complex nanoscale materials and devices.

Main Methods:

• Synergistic combination of vapor-liquid-solid nanowire growth, selective coaxial lithography via etching of surfaces (SCALES), and area-selective atomic layer deposition (AS-ALD).
• Growth of silicon nanowires with axially modulated n-Si/i-Si dopant profiles.
• Application of SCALES to create coaxial poly(methyl methacrylate) (PMMA) masks on n-Si regions.
• Area-selective atomic layer deposition (AS-ALD) of ZrO2 on exposed i-Si regions, avoiding PMMA-masked areas.

Main Results:

• Demonstrated programmable deposition of ZrO2 thin films on Si nanowires.
• Confirmed spatial alignment of ZrO2 films with the underlying n-Si/i-Si dopant profile.
• Showcased nanoscale resolution in controlling film deposition based on dopant distribution.

Conclusions:

• The integrated bottom-up process offers precise control over nanoscale material fabrication.
• The technique is adaptable to various materials and dopant profiles due to AS-ALD versatility.
• This approach opens new avenues for creating complex nanostructures and electronic devices.