Single-wafer polysilicon engineering for the improvement of over erase in a 0.18-(mu)m floating-gate flash memory

A new polysilicon grain engineering technology for the improvement of over erase in 0.18-(mu)m floating-gate flash memory has been developed with the use of single-wafer polysilicon processing, which makes it practical to use hydrogen as a process variable. The addition of hydrogen in polysilicon deposition significantly alters the reaction kinetics and produces polysilicon thin film of smooth surface, fine and uniformly distributed grains. Such a micrograin polysilicon possesses show excellent high-temperature stability. The benefits of the micrograin polysilicon are to be demonstrated through its improvement in over erase of a 0.18-(mu)m floating-gate flash memory.