High-Field Breakdown and Thermal Characterization of Indium Tin Oxide Transistors

Area of Science:

• Materials Science
• Semiconductor Physics
• Nanotechnology

Background:

• Amorphous oxide semiconductors offer low-temperature fabrication for transistors.
• Self-heating effects can limit performance due to low thermal conductivity and heterogeneous interfaces.

Purpose of the Study:

• Investigate high-field breakdown mechanisms in ultrathin amorphous indium tin oxide (ITO) transistors.
• Analyze the impact of different substrates (SiO2 and HfO2) on device performance and failure modes.

Main Methods:

• Utilized scanning thermal microscopy (SThM) to measure channel temperatures during breakdown.
• Employed multiphysics simulations to model thermal and mechanical stresses.
• Estimated thermal boundary conductance between ITO and substrates.

Main Results:

• ITO transistors failed irreversibly at channel temperatures of ~180°C (SiO2) and ~340°C (HfO2).
• Failure was attributed to thermally-induced compressive strain near device contacts.
• Thermal boundary conductance was determined: 35 ± 12 MWm⁻²K⁻¹ (ITO/SiO2) and 51 ± 14 MWm⁻²K⁻¹ (ITO/HfO2).

Conclusions:

• HfO2 substrates offer superior heat dissipation and thermal expansion matching, leading to higher breakdown power.
• Thermo-mechanical limitations are critical for reliable amorphous oxide transistor applications.
• Findings guide the development of high-performance logic and memory devices.