Critical temperature in feedback-controlled electromigration of gold nanostructures

Area of Science:

• Materials Science
• Solid-State Physics
• Electrical Engineering

Background:

• Electromigration (EM) is a critical failure mechanism in microelectronics.
• Current models often assume a fixed critical junction temperature for EM onset.
• This assumption may oversimplify EM behavior in real devices.

Purpose of the Study:

• To investigate the factors influencing the critical temperature for electromigration.
• To challenge the notion of a single, fixed critical junction temperature for EM.
• To provide a more nuanced understanding of EM onset conditions.

Main Methods:

• Performed feedback-controlled electromigration experiments on nanowires and bowtie structures.
• Varied environmental temperatures (75-260 K), thermal resistance, and current flow direction.
• Utilized constant junction power models and various thermal models to analyze data.

Main Results:

• Critical junction temperature (T_c) for EM varies with environmental temperature, thermal resistance, and current direction.
• Fit critical power increased non-linearly with decreasing temperature.
• T_c was found to depend on adjacent thermal resistance and electron flow alignment.

Conclusions:

• The critical temperature for electromigration is not a constant but a variable dependent on multiple parameters.
• Environmental temperature, thermal resistance, and current direction significantly influence EM onset.
• A more complex model is needed to accurately predict electromigration in microelectronic devices.