硅量子点双势垒存储结构及其编程机制的研究

Study of structure of Si QDs memory with double barrier and its programming mechanism

采用等离子体化学气相沉积(PECVD)及热退火方法制备了含硅量子点的Si Cx薄膜.透射电子显微镜(TEM)观测表明Si Cx薄膜中生长了大量硅量子点.制备了含Si Cx薄膜包裹硅量子点的双势垒存储器结构.TEM观测表明,采用上述工艺成功制备了Si3N4/Si Cx薄膜/Si-QDs/Si Cx薄膜/Si O2双势垒结构的存储器结构.利用硅量子点的库伦阻塞效应及量子限域效应,从理论上分析了双势垒硅量子点存储器的编程机制,建立了双势垒存储结构阈值电压漂移模型,模拟仿真表明双势垒存储器的阈值电压漂移要大于单势垒存储器,编程速度更快.存储结构C-V特性测试表明,样品在扫描栅压为±12 V时有10 V左右的存储窗口,证明双势垒存储结构具有良好载流子存储效应.

SiCx thin films with silicon quantum dots（QDs） were prepared by plasma enhanced chemical vapor deposition（PECVD） and thermal annealing. Transmission electron microscopy（TEM） observation shows that a large number of silicon QDs growing in Si Cx films. Memory structure with double barrier which consist of Si Cx thin films embedded in silicon QDs were prepared. TEM observations shows that the above process successfully prepared Si3N4/Si Cx/Si-QDs/Si Cx/Si O2 double-barrier memory structure. The programming mechanism of double-barrier silicon quantum dot memory was analyzed theoretically in consideration of coulomb blockade effects and quantum confinement effect of silicon quantum QDs. The threshold voltage shift model of double-barrier structure was established. Simulation of that mode shows that threshold voltage shift of double barrier memory is larger than a single barrier memory and double-barrier memory programming faster too. C-V characteristic tests of storage structure shows that double-barrier structure has good storage carrier storage effect, getting about 10 V＇s the storage window when the scan voltage is ±12 V.