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.
JESD22-A117
Meaning
Standardized testing procedures developed by the JEDEC Solid State Technology Association establish the methods for evaluating the endurance and data retention of non-volatile solid-state memory devices. The document designated as jesd22-a117 defines the stress conditions used to qualify integrated circuit memory cells. It ensures that memory blocks can withstand repeated write cycles and retain data over long periods.
Stress Protocol
Thermal chambers apply elevated temperatures to the memory devices during the cycling and retention phases of the evaluation. Accelerated testing speeds up the natural degradation of the dielectric layers. Technicians measure the charge loss of the floating gates after exposure.
Qualification Criterion
Device failure occurs if the memory cannot be read correctly after undergoing the specified number of write cycles. The standard provides clear pass or fail thresholds based on bit error rates. Semiconductor manufacturers must satisfy these requirements to certify their products for automotive use.
Test Sequence
Sequential stress steps simulate the entire operational lifespan of the chip within a compressed timeframe. Technicians subject the memory to electrical cycling at high temperatures to wear down the silicon dioxide barrier. After cycling, the device undergoes a high-temperature bake to evaluate passive retention.
Analyzing the resulting data helps designers optimize the oxide thickness and gate geometry for future product revisions.