Meaning
Electronic transport through insulating films mediated by the thermal emission of trapped carriers into the conduction band limits device reliability under high fields. When high voltages are applied to thin dielectric layers, poole frenkel conduction occurs as the electric field lowers the potential barrier of localized traps. This leakage mechanism is highly temperature-dependent and is common in semiconductor memory devices and gate oxides.
Physics Process
Conduction occurs when electrons are thermally excited out of the lowered potential wells. This poole frenkel conduction exhibits a characteristic linear relationship when the logarithm of current density divided by field strength is plotted against the square root of the field. This behavior distinguishes it from other conduction mechanisms like Fowler-Nordheim tunneling.
Thermal Stress
Operating temperatures directly accelerate the leakage current through the dielectric layer. This thermal sensitivity must be evaluated when designing devices for high temperature industrial environments.
Diagnostic Test
Current-voltage sweeps across a range of temperatures are used to confirm the presence of this conduction mode. Engineers perform these sweeps on test structures to qualify dielectric materials for integrated circuits. The results of these tests determine the maximum safe operating field strength for the device.
This characterization is a standard step in the reliability handover package for new semiconductor nodes.
