Monitoring Methodology for TID Damaging of SDRAM Devices based on Retention Time Analysis (original) (raw)

Total Ionizing Dose Effects on DRAM Data Retention Time

IEEE Transactions on Nuclear Science, 2014

DRAM data retention time degradation induced by radiation exposure is investigated in this paper. We present the experimental setup and the results of TID test on a COTS SDRAM device. We observed a significant retention time reduction proportional to the absorbed dose and we assume radiation induced interface trap generation as the origin of the retention time reduction. By measuring individual cells retention time before and after radiation exposures, we found out that the reduction is not homogeneous among cells: the amount of leakage current increase depends on the position and the energy level of the generated trap, leading to a wide distribution of retention time reduction. Of particular interest is the fact that device was unbiased during irradiation and that no post-irradiation recovery was observed.

TCAD simulation of radiation-induced leakage current in 1T1C SDRAM

Microelectronics Reliability, 2018

In order to identify the physical mechanism of retention time drop in irradiated SDRAM cell, we implemented the Gossick model of displacement damage cluster into a TCAD simulation tool. Simulation results show that the cluster's position is the key parameter of the phenomenon. Besides that, obtained results are coherent with previous studies and explained by semiconductor physics. Other technological parameters of the cell also influence its response to displacement damage clusters. Leakage current induced by clusters depends exponentially on temperature.

Proton-Induced Single-Event Degradation in SDRAMs

IEEE Transactions on Nuclear Science, 2016

Retention time and cell functionality degradation under proton irradiation is studied for SDRAM references that exhibit in-flight faulty behavior on satellites. Proton irradiation, with an adapted test protocol, allows to reproduce these effects and to gain a valuable insight on this phenomenon. Data acquired allow for a physical interpretation of the degradation, which results of one or more damage clusters created by a single particle.

Characterization of data retention faults in DRAM devices

2014 IEEE International Symposium on Defect and Fault Tolerance in VLSI and Nanotechnology Systems (DFT), 2014

Dynamic random access memory (DRAM) is the most widely used type of memory in the consumer market today, and it's still widely used for mass memories for space application. Even though accurate tests are performed by vendors to ensure high reliability, DRAM errors continue to be a common source of failures in the field. Recent large-scale studies reported how most of the errors experienced by DRAM subsystem are due to faults repeating on the same memory address but occurring only under specific condition.

Radiation Induced Variable Retention Time in Dynamic Random Access Memories

IEEE Transactions on Nuclear Science, 2020

The effect of gamma-ray and neutron radiations on the Variable Retention Time (VRT) phenomenon occurring in Dynamic Random Access Memory (DRAM) is studied. It is shown that both ionizing radiation and non-ionizing radiation induce VRT behaviors in DRAM cells. It demonstrates that both Si/SiO2 interface states and silicon bulk defects can be a source of VRT. It is also highlighted that radiation induced VRT in DRAMs is very similar to radiation induced Dark Current Random Telegraph Signal (DC-RTS) in image sensors. Both phenomena probably share the same origin but high magnitude electric fields seem to play an important role in VRT only. Defect structural fluctuations (without change of charge state) seem to be the root cause of the observed VRT whereas processes involving trapping and emission of charge carriers are unlikely to be a source of VRT. VRT also appears to be the most probable cause of intermittent stuck bits in irradiated DRAMs.

Characterization Summary for a Radiation Hardened 16KX1 SRAM

IEEE Transactions on Nuclear Science, 2000

A radiation-hard 16kxl SRAM with a typical access time of less than 100 ns and total dose hardness to 1 E6 rads(SiO2) has been developed. Extensive radiation characterization has been performed with the aid of a test system developed to support testing in various radiation environments including total dose, dose rate upset, dose rate survival, dose rate photocurrent, and single event upset. Total dose testing of the 16kxl included characterization of critical ac timing parameters as a function of dose as well as observation of standby current behavior as a function of array pattern. Dose rate tests were designed to explore the SRAM's sensitivities to Vdd, temperature, memory cell resistor value, dose rate pulse width, operational mode, and array pattern. Single event upset testing was also performed under a matrix of test conditions, including variations in supply voltage, temperature, memory cell resistor value, and particle angle of incidence. This paper describes 16kxl SRAM radiation test procedures and characterization test results.

Application of IDDT test towards increasing SRAM reliability in nanometer technologies

2012 IEEE 15th International Symposium on Design and Diagnostics of Electronic Circuits & Systems (DDECS), 2012

Dynamic supply current test method (I DDT test) in static random access memory (SRAM) cell arrays is addressed in order to unveil weak open defects. Simulations were carried out on a 64-bit SRAM circuit, where several parameters of the I DDT waveform were monitored. The SRAM circuit was designed in a 90 nm CMOS technology. Efficiency of I DDT test in unveiling open defects was evaluated and the achieved results were compared for four SRAM arrays with cells of different cell ratio (CR). Moreover, a solution for transformation of the dynamic current to voltage is presented. After the transformation of the current waveform to a voltage waveform, the parameters of the voltage waveform similar to those of the current waveform are easily monitored and evaluated.

Total Ionizing Dose Effects on Data Retention Capabilities of Battery-Backed CMOS SRAM

IEEE Transactions on Nuclear Science, 2000

Abstract-Data retention capabilities of commercial batterybacked static random access memories (SRAMs) exposed to different ionizing dose are investigated. Pattern imprinting is observed for devices exposed to a total dose of 50 kR and above. Room temperature annealing and recovery is also recorded. A model for the pattern imprinting behavior in SRAMs is presented based on the general understanding of defects produced in MOSFETs due to ionizing radiation.

Bulk damage caused by single protons in SDRAMs

IEEE Transactions on Nuclear Science, 2003

A new failure mode that is attributable to the bulk damage caused by single protons has been reported in 256-Mbit SDRAMs. The refresh rate required to retain memorized data was measured as a typical parameter to detect the effect. We performed the proton irradiation test and discussed results regarding the influence of this failure.

Radiation effects on advanced flash memories

IEEE Transactions on Nuclear Science, 1999

Radiation tests of advanced flash memories including, multi-level flash technology, are compared with results from previous generations. Total dose failure levels are comparable to or lower than those of older technologies, but are likely still caused by degradation of the internal charge pump. Small numbers of read errors were observed during single event tests of the multi-level devices that appear to be caused by shifts in the sense amplifier detection levels or cell threshold shifts and rather than loss of electrons off the floating gate.