Modeling and simulation of ZnO-based TFTs by dielectric engineering and temperature analysis for enhanced performance

Area of Science:

• Semiconductor Device Physics
• Materials Science

Background:

• Thin-film transistors (TFTs) are crucial for electronic devices.
• Zinc oxide (ZnO) is a promising material for TFTs due to its properties.
• Understanding the analog performance of ZnO TFTs is essential for device optimization.

Purpose of the Study:

• To model and simulate ZnO-based TFTs.
• To investigate the impact of gate dielectric material, thickness, and operating temperature on TFT performance.
• To optimize ZnO TFTs for high-performance analog and optoelectronic applications.

Main Methods:

• Device modeling and simulation of ZnO TFTs.
• Experimental validation of the device model.
• Systematic analysis of electrical parameters (ID, µFE, SS, VTh, Ion/Ioff) under varying conditions.
• Temperature-dependent analysis to understand performance degradation.

Main Results:

• The developed ZnO TFT model showed strong agreement with experimental data.
• Hafnium oxide (HfO₂) demonstrated superior performance among tested dielectrics (SS = 0.396 V/dec, VTh = 0.49 V, µFE = 53.2 cm²/V·s).
• Optimized HfO₂ (120 nm) yielded enhanced characteristics: µFE = 54.2 cm²/V·s, VTh = 0.27 V, SS = 0.315 V/dec, Ion/Ioff ≈ 10¹¹.
• Device performance decreased at temperatures above 400 K due to trap effects and Fermi-level shifts.

Conclusions:

• ZnO TFTs, particularly with optimized HfO₂ dielectrics, show significant potential for high-performance analog and optoelectronic applications.
• Optimal performance is achieved at room temperature.
• The study provides a validated model and insights into parameter optimization for circuit designers.