二維過渡金屬硫屬化合物及堆疊式奈米線元件之靜態隨機存取記憶體分析與研究

Abstract

本論文針對二維過渡金屬硫屬化合物(2-D Transition-Metal Dichalcogenide)元件構成靜態隨機存取記憶體(SRAMs)性能及穩定性提供完整的分析與評估。我們的研究指出，立體式的二維材料場效電晶體比傳統平面式的二維材料場效電晶體可以提供更高的穩定性以及性能。 我們對於二維過渡金屬硫屬化合物元件的研究並不僅僅停留在基本的平面與立體元件的比較，也擴展到混成矽/二維材料堆疊式雙通道互補式金屬氧化物半導體元件。我們利用這個特別的元件提出了只用4個元件即可組成傳統六元件靜態隨機存取記憶體的想法。因為這樣，我們可以節省電路面積同時也提供了足夠的讀取穩定度以及非常好的寫入效率。 除了對二維過渡金屬硫屬化合物元件的研究，我們也針對現在很熱門的堆疊式矽奈米線元件研究這個元件在靜態隨機存取記憶體上的應用。我們發現寄生電阻會對於靜態隨機存取記憶體的讀寫穩定度有很大的影響。我們也發現對於高密度的靜態隨機存取記體來說後端製成的寄生電容需要被很小心的考慮。

This thesis comprehensively investigates the 2D Transition-Metal- Dichalcogenide (TMD) de-vices targeting the ITRS 2028 (5.9nm) technology node with the aid of TCAD numerical sim-ulation. We benchmark the difference between non-planar and planar 2D TMD devices for standard 6T SRAM cells. Our study indicates that the non-planar 2D SRAM can possess higher cell stability and performance than the planar one. We have also explored and evaluated the feasibility of a novel hybrid Si/TMD stacked dual-channel CMOS technology. A novel 4T SRAM cell is proposed with reduced the cell ar-ea and comparable read stability and superior write-ability as compared with the standard 6T SRAM. In addition, we have evaluated the vertically stacked nanowires for SRAM applications. Our study indicates that the contact resistance may significantly degrade the read/write stabil-ity and the back-end-of-line parasitic capacitance needs to be carefully considered for the stacked nanowire SRAM.