Cocktail Precursor Approach for Homogeneous ALD InGaO Film Growth Overcoming Limits of Mobility-Reliability Trade-Off...

Area of Science:

• Materials Science
• Semiconductor Physics
• Nanotechnology

Background:

• Crystalline indium gallium oxide (IGO) is a key material for high-performance field-effect transistors (FETs) due to its thermal stability and high mobility.
• Achieving uniform composition and optimal structure in IGO films is crucial for device performance.

Purpose of the Study:

• To develop a novel cocktail precursor strategy for atomic layer deposition (ALD) of uniform IGO thin films.
• To investigate the impact of this strategy on film properties and FET performance.

Main Methods:

• A cocktail precursor strategy using a 3:1 molar mixture of In (DMITN) and Ga (DMGTN) precursors was employed for ALD.
• Thermal analysis, ALD growth characterization, and structural analysis were performed.
• Field-effect transistors (FETs) were fabricated using the synthesized IGO films.

Main Results:

• The cocktail precursor demonstrated homogeneous behavior and thermal stability.
• ALD growth showed self-limiting reactions and improved efficiency over supercycle methods.
• IGO films exhibited homogeneous cation distribution, improved crystallographic alignment, reduced defects, and enhanced out-of-plane orientation.
• FETs with cocktail precursor-derived IGO channels showed a 28% increase in field-effect mobility (61.8 cm²/V·s), lower trap densities, and superior bias temperature stress stability.
• Excellent wafer-scale reproducibility was achieved.

Conclusions:

• The cocktail precursor approach enables the deposition of compositionally homogeneous and structurally well-ordered IGO films.
• This method effectively addresses the mobility-reliability trade-off in oxide semiconductors.
• The developed strategy is highly suitable for fabricating high-performance oxide semiconductor devices.