US Patent 7639533 Multi-level memory cell programming methods

A method for programming a plurality of multi-level memory cells described herein includes iteratively changing a bias voltage applied to a first memory cell to program the first memory cell to a first threshold state and detecting when the first cell reaches a predetermined threshold voltage. The bias voltage applied to the first memory cell upon reaching the predetermined threshold voltage is recorded. A second memory cell is programmed to a second threshold state by applying an initial bias voltage to the second memory cell which is function of the recorded bias voltage.