Related Experiment Video
Updated: Jan 10, 2026
12:32
The Effect of Anodization Parameters on the Aluminum Oxide Dielectric Layer of Thin-Film Transistors
Published on: May 24, 2020
9.2K
High-Mobility IZO Thin-Film Transistors Enabled by Precise Hydrogen Control Using a SiO2-Al2O3 Supercycle via
Sunghwan Park1, Seong-In Cho2, Hwa Young Kim1
1Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea.
ACS Applied Materials & Interfaces
|November 25, 2025
Summary
Precise control of hydrogen in oxide thin-film transistors (TFTs) is achieved using a plasma-enhanced atomic layer deposition (PEALD) supercycled gate insulator. This method optimizes hydrogen levels for enhanced mobility and stability in high-performance TFTs.
Area of Science:
- Materials Science
- Semiconductor Physics
- Thin-Film Electronics
Background:
- Hydrogen incorporation critically influences carrier concentration and defect passivation in oxide thin-film transistors (TFTs).
- Achieving precise control over hydrogen levels is vital for optimizing TFT performance and stability.
- Existing methods for hydrogen control in oxide semiconductors present challenges in achieving fine-tuned modulation.
Purpose of the Study:
- To develop a novel strategy for precise hydrogen control in oxide TFTs using a plasma-enhanced atomic layer deposition (PEALD) supercycled gate insulator.
- To investigate the impact of varying hydrogen incorporation levels on the electrical characteristics and stability of oxide TFTs.
- To optimize the hydrogen content for achieving a balance between high mobility and robust bias stability.
Main Methods:
- Fabrication of top-gate oxide TFTs employing a supercycled SiO2-Al2O3 gate insulator via PEALD.
- Systematic variation of hydrogen incorporation by adjusting the number of hydrogen-rich SiO2 subcycles within the supercycle.
- Comprehensive electrical characterization, including field-effect mobility, turn-on voltage, subthreshold swing, on/off current ratio, and bias stability testing.
Main Results:
- Moderate hydrogen incorporation (10 cycles of H-rich SiO2) effectively passivates defects, introduces shallow donor states, enhances mobility (47.4 cm²/V·s), and improves bias stability.
- Optimized devices exhibit a low turn-on voltage (-0.46 V), sharp subthreshold swing (71.3 mV/dec), negligible hysteresis, and a high on/off ratio (∼10⁷).
- Excessive hydrogen (15 cycles) leads to gate insulator intermixing, uncontrolled diffusion, excessive carrier generation, and loss of switching behavior.
Conclusions:
- The PEALD supercycle process provides a reliable and tunable method for precise hydrogen modulation in oxide semiconductors.
- This approach enables an optimized trade-off between carrier mobility and operational stability in high-performance TFTs.
- The findings highlight the potential of controlled hydrogen incorporation for advancing oxide semiconductor device technology.
