Non-Volatile Memory Charge Retention Mechanics under High-Temperature Environments
High ambient heat accelerates non-volatile memory charge leakage through thermionic emission and trap tunneling, degrading stored radio calibration data over time.
Interface States
Meaning
Electronic energy levels residing within the band gap at the physical junction of two dissimilar materials. These interface states result from disrupted crystal symmetry or the presence of impurities at the oxide and semiconductor boundary. They act as trapping centers for charge carriers, effectively reducing the mobility of electrons in the channel of a transistor.
High densities of these states lead to threshold voltage shifts and increased subthreshold swing.
Trap Density
Quantitative measurement of these electronic sites determines the quality of the passivation layer. A high concentration of interface states indicates poor atomic bonding at the junction.
Charge Accumulation
Trapping of carriers at the boundary alters the local electric field during device operation. When interface states capture electrons, they create a fixed charge that opposes the applied gate voltage. Such behavior leads to hysteresis in the capacitance and voltage characteristics.
Physical properties of the dielectric influence how quickly these charges dissipate. Stability of the device depends on minimizing this parasitic charge buildup.
Thermal Impact
Temperature variations influence the rate at which carriers move in and out of these boundary levels. Increased thermal energy allows more carriers to overcome the energy barrier and populate the interface states. Consequently, the leakage current increases as the device heats up.
High temperatures accelerate the degradation of the interface during long term operation.