The Evaluation of Interface Quality in HfO₂ Films Probed by Time-Dependent Second-Harmonic Generation

Area of Science:

• Materials Science
• Semiconductor Physics
• Optoelectronics

Background:

• Oxide/Si heterostructures are crucial in semiconductor devices.
• Interfacial electric fields significantly impact device performance.
• Accurate interface quality evaluation is essential for reliable semiconductor manufacturing.

Purpose of the Study:

• To investigate the utility of time-dependent second-harmonic generation (TD-SHG) for evaluating the interface quality of HfO2 films on Si substrates.
• To correlate TD-SHG parameters with conventional electrical characterization metrics.

Main Methods:

• Utilized time-dependent second-harmonic generation (TD-SHG) as a characterization technique.
• Deposited HfO2 films on Si substrates using atomic layer deposition.
• Compared TD-SHG initial signal and time constant with fixed charge density (Qox) and interface state density (Dit).

Main Results:

• The initial SHG signal showed a linear decrease with increasing Qox.
• The characteristic time constant correlated linearly with Dit.
• TD-SHG demonstrated sensitivity to interfacial properties.

Conclusions:

• TD-SHG is a sensitive, fast, simple, and noncontact method for evaluating oxide/Si heterostructure interface quality.
• The method shows potential for in-line semiconductor testing and quality control.
• TD-SHG provides a valuable alternative to conventional electrical characterization methods.