Annealing of thin B/Nb2N bilayers, B/Nb bilayers and Nb/B/Nb trilayers via rapid thermal processing (RTP)

Area of Science:

• Materials Science
• Thin Film Technology
• Surface Science

Background:

• Investigating the properties of thin films is crucial for advanced electronic applications.
• Understanding the diffusion and reactivity of elements like niobium (Nb), boron (B), and nitrogen (N) in thin film structures is key to developing new materials.

Purpose of the Study:

• To analyze the interdiffusion and reactivity of niobium, boron, and nitrogen in B/Nb and B/Nb(2)N bilayers and Nb/B/Nb trilayers.
• To determine the effectiveness of niobium nitride (Nb(2)N) as a diffusion barrier for boron.

Main Methods:

• Thin films were deposited using magnetron sputtering and rapid thermal processing (RTP).
• Phase formation was analyzed using X-ray diffraction (XRD).
• Surface morphology and roughness were examined with scanning electron microscopy (SEM) and atomic force microscopy (AFM), respectively. Elemental depth profiles were obtained via secondary ion mass spectrometry (SIMS).

Main Results:

• Annealing B/Nb bilayers and Nb/B/Nb trilayers under Argon (Ar) at 1,200°C resulted in Nb(3)B(2) formation.
• High oxygen content in boron layers hindered boride formation at lower temperatures due to boron oxide formation.
• Annealing in ammonia (NH(3)) led to niobium nitride formation but suppressed boride formation.
• Annealing B/Nb(2)N bilayers showed no boride formation, indicating Nb(2)N acts as an effective diffusion barrier.

Conclusions:

• Niobium nitride (Nb(2)N) is an effective diffusion barrier for boron in thin film structures.
• Oxygen contamination in boron layers significantly impacts boride formation kinetics.
• Controlled annealing environments (Ar vs. NH(3)) influence the resulting phases in niobium-boron-nitrogen systems.