Pub Date : 2024-09-02DOI: 10.1109/TDMR.2024.3453329
Linxin Yin;Yingzhao Li;Xiaoyi Zhang;Xiongfei Zhai;Guojun Han
With high storage density and large capacity, three-dimensional (3D) NAND flash utilizing multi-level storage technology has become the mainstream storage medium. Furthermore, by storing multiple bits in each flash cell, 3D NAND flash memory can achieve much larger storage capacity. However, the threshold voltage distribution in 3D NAND flash memory tends to shift after repeated program/erase and long retention time, leading to more detection error when adopting conventional fixed read reference voltage (RRV). To address this issue, in this work we investigate error characteristics of 3D floating-gate (FG) and charge-trap (CT) NAND flash memory, including the reliability variations of different layers and pages, and threshold voltage shifting. We propose an efficient dynamic threshold voltage detection (EDTVD) scheme by exploiting the error characteristics and the features of the data writing process of NAND flash to optimize RRV. Based on the Nanocycler test platform, the test results show that our proposed scheme can significantly reduce raw bit error rates (RBER) during reading processes and the step count is relatively low. The RBER of the EDTVD scheme is almost equal to the optimal read scheme, and the number of step count is close to 3 fixed-step read scheme.
{"title":"An Efficient Dynamic Threshold Voltage Detection Scheme for Improving 3-D NAND Flash Reliability","authors":"Linxin Yin;Yingzhao Li;Xiaoyi Zhang;Xiongfei Zhai;Guojun Han","doi":"10.1109/TDMR.2024.3453329","DOIUrl":"10.1109/TDMR.2024.3453329","url":null,"abstract":"With high storage density and large capacity, three-dimensional (3D) NAND flash utilizing multi-level storage technology has become the mainstream storage medium. Furthermore, by storing multiple bits in each flash cell, 3D NAND flash memory can achieve much larger storage capacity. However, the threshold voltage distribution in 3D NAND flash memory tends to shift after repeated program/erase and long retention time, leading to more detection error when adopting conventional fixed read reference voltage (RRV). To address this issue, in this work we investigate error characteristics of 3D floating-gate (FG) and charge-trap (CT) NAND flash memory, including the reliability variations of different layers and pages, and threshold voltage shifting. We propose an efficient dynamic threshold voltage detection (EDTVD) scheme by exploiting the error characteristics and the features of the data writing process of NAND flash to optimize RRV. Based on the Nanocycler test platform, the test results show that our proposed scheme can significantly reduce raw bit error rates (RBER) during reading processes and the step count is relatively low. The RBER of the EDTVD scheme is almost equal to the optimal read scheme, and the number of step count is close to 3 fixed-step read scheme.","PeriodicalId":448,"journal":{"name":"IEEE Transactions on Device and Materials Reliability","volume":"24 4","pages":"529-543"},"PeriodicalIF":2.5,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142181554","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-15DOI: 10.1109/TDMR.2024.3442781
Yongdong Wu;Bin He;Jingyuan Fang;Yuqi Hu;Xiaoliang Zeng;Linlin Ren;Rong Sun
With the growing power density and miniaturization of electronic devices, their thermal management and reliability are becoming more and more important. Polymer-based thermal interface materials, which are used to fill the gap between chip and heat sink, play an important role for the heat dissipation, but their reliability is rarely studied in academia, especially under thermo-oxidative condition. Here, a polymer-based thermal interface material, highly filled thermal conductive gel, is used as a model to study the degradation mechanism under thermo-oxidative condition. The results show that aging mainly deteriorates the mechanical performance instead of its intrinsic thermal conductivity. The elongation at break of aged sample is reduced and the corresponding modulus is increased as a function of aging time. Relaxation spectra indicate that the relaxation time of aged sample increases. The longer relaxation time of aged sample is attributed to the chain scission and oxidation of alky chain at interface and the depolymerization of polydimethylsiloxane chain, resulting in a more crosslinked polymer network. Thus, both interfacial aging and depolymerization of polymers contribute to the slowdown of polymer chain dynamics and degradation of mechanical properties. This work provides an insight into the degradation mechanism of thermal interface materials and guides the development of high-reliability thermal interface materials.
{"title":"Unveiling the Degradation Mechanism of Polymer-Based Thermal Interface Materials Under Thermo-Oxidative Condition","authors":"Yongdong Wu;Bin He;Jingyuan Fang;Yuqi Hu;Xiaoliang Zeng;Linlin Ren;Rong Sun","doi":"10.1109/TDMR.2024.3442781","DOIUrl":"10.1109/TDMR.2024.3442781","url":null,"abstract":"With the growing power density and miniaturization of electronic devices, their thermal management and reliability are becoming more and more important. Polymer-based thermal interface materials, which are used to fill the gap between chip and heat sink, play an important role for the heat dissipation, but their reliability is rarely studied in academia, especially under thermo-oxidative condition. Here, a polymer-based thermal interface material, highly filled thermal conductive gel, is used as a model to study the degradation mechanism under thermo-oxidative condition. The results show that aging mainly deteriorates the mechanical performance instead of its intrinsic thermal conductivity. The elongation at break of aged sample is reduced and the corresponding modulus is increased as a function of aging time. Relaxation spectra indicate that the relaxation time of aged sample increases. The longer relaxation time of aged sample is attributed to the chain scission and oxidation of alky chain at interface and the depolymerization of polydimethylsiloxane chain, resulting in a more crosslinked polymer network. Thus, both interfacial aging and depolymerization of polymers contribute to the slowdown of polymer chain dynamics and degradation of mechanical properties. This work provides an insight into the degradation mechanism of thermal interface materials and guides the development of high-reliability thermal interface materials.","PeriodicalId":448,"journal":{"name":"IEEE Transactions on Device and Materials Reliability","volume":"24 4","pages":"514-521"},"PeriodicalIF":2.5,"publicationDate":"2024-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142223807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
SiC IGBTs take the advantages of high breakdown voltage and high conduction current, being a new type of power device with great application prospects in power transmission fields. However, foreseeable stress conditions such as gate stress, irradiation, and bipolar conduction may cause damage to the gate oxide and the epitaxial layer of SiC IGBTs, leading to degradation. Analysis of the device capacitance components shows that the damages in the gate oxide and the epitaxial layer results in variations in the gate capacitance and the substrate junction capacitance before and after enduring a stress. Therefore, the all-regions damage extraction method for SiC IGBT based on C-V curves is proposed for the first time. This method divides the ${C}_{text {G}}$