과도한 채널 이온 주입 농도 및 Si-SiN 스트레스가 플래쉬 메모리셀 산포에 미치는 영향

The study on cell Vth distibution induced by heavily doped channel ionn and Si-SiN stress in flash memory cell

As scaling down the cell channel length, the increment of B concentration in channel region is inevitable to overcome the punch-through, especially in flash memory cell with 90nm technology. This paper shows that the high dose ion implantation in channel cause the Si defect. which has been proved to be the major cause of the tailed Vth in distribution. And also mechanical stress due to SiN-anneal process can induce the Si dislocation. and get worse it. With decreasing the channel implantation dose, skipping the anneal and reducing the mechanical stress, Si defect problem is solved completely. We are verify first that the optimization of B concentration in channel must be certainly considered in order to improve Si defect. It is also certainly necessary to stabilize the distribution of cell Vth in the next generation of flash memory.