Si single-electron MOS memory with nanoscale floating-gate and narrow channel

Floating-gate MOS memories based on single electron effect are very attractive, because of the potential quantized threshold voltage shift, quantized charging voltage to create the shift, small device size and fast charging time. However, to relax the challenges in fabricating such devices, previous single-electron MOS memories (SEMMs) had to have nonconventional structures (e.g. a polysilicon channel or a floating gate consisting of many isolated silicon nanocrystals), causing large fluctuation in device dimension and performance and making them unsuitable to ULSI. Here we present the first SEMMs having a narrow crystalline Si channel and a nanoscale poly-Si floating gate of a well controlled dimension. We report that charging of a single electron to the floating gate will lead to, at room temperature, quantized threshold voltage shift, discrete charging voltage, and self-limiting charging process.