Atomic scale interface engineering for strain compensated epitaxially grown InAs/AlSb superlattices.

Area of Science:

• Materials Science
• Solid State Physics
• Semiconductor Heterostructures

Background:

• Indium arsenide/aluminum antimonide (InAs/AlSb) superlattices are critical for high-speed electronics.
• Achieving strain compensation in these heterostructures is essential for device performance and material stability.

Purpose of the Study:

• To systematically investigate strain compensation strategies for InAs/AlSb superlattices grown on Gallium antimonide (GaSb) substrates.
• To explore the impact of growth interruptions and arsenic/antimony fluxes on strain management.

Main Methods:

• Utilized short growth interruptions (soak times) with controlled arsenic and antimony beam fluxes.
• Investigated the effect of cracked As(2) dimers versus uncracked As(4) on interface formation.
• Employed high-resolution X-ray diffraction and transmission electron microscopy for material characterization.

Main Results:

• Strain compensation was unachievable with uncracked As(4) without AlAs spikes.
• Cracked As(2) directly formed strain-compensating AlAs-like interfaces.
• Enabled soak-time-free and Sb-soak-only growth sequences for superlattices.

Conclusions:

• Cracked As(2) is a key enabler for effective strain compensation in InAs/AlSb superlattices.
• The developed methods yield high-quality layers with minimal heterointerface intermixing.
• These findings facilitate the fabrication of advanced semiconductor devices based on InAs/AlSb heterostructures.