In this work, the total ionizing dose（TID） effect on 130 nm partially depleted（PD） silicon-on-insulator（SOI） static random access memory（SRAM） cell stability is measured. The SRAM cell test structure allowing ...In this work, the total ionizing dose（TID） effect on 130 nm partially depleted（PD） silicon-on-insulator（SOI） static random access memory（SRAM） cell stability is measured. The SRAM cell test structure allowing direct measurement of the static noise margin（SNM） is specifically designed and irradiated by gamma-ray. Both data sides＇ SNM of 130 nm PD SOI SRAM cell are decreased by TID, which is different from the conclusion obtained in old generation devices that one data side＇s SNM is decreased and the other data side＇s SNM is increased. Moreover, measurement of SNM under different supply voltages（Vdd） reveals that SNM is more sensitive to TID under lower Vdd. The impact of TID on SNM under data retention Vddshould be tested, because Vddof SRAM cell under data retention mode is lower than normal Vdd.The mechanism under the above results is analyzed by measurement of I–V characteristics of SRAM cell transistors.展开更多
An accelerated evaluation method for the SRAM cell write margin is proposed using the conventional Write Noise Margin (WNM) definition based on the “butterfly curve”. The WNM is measured under a lower word line volt...An accelerated evaluation method for the SRAM cell write margin is proposed using the conventional Write Noise Margin (WNM) definition based on the “butterfly curve”. The WNM is measured under a lower word line voltage than the power supply voltage VDD. A lower word line voltage is chosen in order to make the access transistor operate in the saturation mode over a wide range of threshold voltage variation. The final WNM at the VDD word line voltage, the Accelerated Write Noise Margin (AWNM), is obtained by shifting the measured WNM at the lower word line voltage. The WNM shift amount is determined from the measured WNM dependence on the word line voltage. As a result, the cumulative frequency of the AWNM displays a normal distribution. Together with the maximum likelihood method, a normal distribution of the AWNM drastically improves development efficiency because the write failure probability can be estimated from a small number of samples. The effectiveness of the proposed method is verified using the Monte Carlo simulation.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.U1532261 and 11605282)the Opening Fund of Key Laboratory of Silicon Device Technology,Chinese Academy of Sciences Research Projects(Grant No.KLSDTJJ2016-07)
文摘In this work, the total ionizing dose（TID） effect on 130 nm partially depleted（PD） silicon-on-insulator（SOI） static random access memory（SRAM） cell stability is measured. The SRAM cell test structure allowing direct measurement of the static noise margin（SNM） is specifically designed and irradiated by gamma-ray. Both data sides＇ SNM of 130 nm PD SOI SRAM cell are decreased by TID, which is different from the conclusion obtained in old generation devices that one data side＇s SNM is decreased and the other data side＇s SNM is increased. Moreover, measurement of SNM under different supply voltages（Vdd） reveals that SNM is more sensitive to TID under lower Vdd. The impact of TID on SNM under data retention Vddshould be tested, because Vddof SRAM cell under data retention mode is lower than normal Vdd.The mechanism under the above results is analyzed by measurement of I–V characteristics of SRAM cell transistors.
文摘An accelerated evaluation method for the SRAM cell write margin is proposed using the conventional Write Noise Margin (WNM) definition based on the “butterfly curve”. The WNM is measured under a lower word line voltage than the power supply voltage VDD. A lower word line voltage is chosen in order to make the access transistor operate in the saturation mode over a wide range of threshold voltage variation. The final WNM at the VDD word line voltage, the Accelerated Write Noise Margin (AWNM), is obtained by shifting the measured WNM at the lower word line voltage. The WNM shift amount is determined from the measured WNM dependence on the word line voltage. As a result, the cumulative frequency of the AWNM displays a normal distribution. Together with the maximum likelihood method, a normal distribution of the AWNM drastically improves development efficiency because the write failure probability can be estimated from a small number of samples. The effectiveness of the proposed method is verified using the Monte Carlo simulation.
