Laser Processing of Ti Contacts for Ohmic Behavior on P‑Type 4H-SiC

Area of Science:

• Materials Science
• Semiconductor Physics
• Electrical Engineering

Background:

• Ohmic contact formation on p-type 4H-silicon carbide (SiC) is critical for power device performance.
• Conventional methods involve high thermal budgets or complex multilayer stacks, limiting scalability and efficiency.

Purpose of the Study:

• To develop a selective, low thermal budget method for ohmic contacts on p-type 4H-SiC.
• To investigate the effects of pulsed laser annealing (PLA) on titanium (Ti) metallization for contact formation.

Main Methods:

• Utilized single Ti metallization combined with PLA on p-type 4H-SiC.
• Applied varying laser fluences (above 3.6 J/cm²) and analyzed current-voltage (I-V) characteristics.
• Employed cross-sectional transmission electron microscopy (TEM) and elemental mapping to characterize interfacial structures.

Main Results:

• PLA fluences above 3.6 J/cm² resulted in linear I-V behavior, indicating ohmic contact formation.
• A 50% improvement in conduction was observed at 3.8 J/cm², attributed to deeper SiC consumption and formation of epitaxial SiC/TiC layers.
• Higher fluences promoted ternary Ti-Si-C phases, enhancing interfacial stability and electrical performance.

Conclusions:

• PLA offers precise control over interfacial reactions and microstructure for ohmic contacts on p-type 4H-SiC.
• This approach is scalable, selective, and thermally efficient, advancing SiC power electronics.
• The developed method facilitates the fabrication of high-performance, next-generation SiC-based power devices.