An Experimental Study on Hot-Hole Injection (HHI) in Floating-Gate (FG) Flash Memory

Inthis work, a comprehensive study is done on the impacts of hot hole injection (HHI) in 55nm NOR flash technology when high-speed pulse scheme is implemented to proceed the erase operation. As narrowing the rising edge to 10ns, a significant enhancement of the erasing efficiency can be obtained. Specially, a memory window (MW) of 0.5V can be realized in 20ns, and 2us is sufficient for 5V MW erasing. Moreover, we monitored and adjusted the HHI operation to tighten the threshold voltage (Vth) distributions for multi-bit operations. More important, it is demonstrated that the cell performances, such as the subthreshold swing (SS) and the leakage current (Ioff), will not degrade when processing the high-speed HHI erasing scheme.