A multi-bit split-gate (MSG) flash cell with multi-shared source/drain, a method
of making and a method of programming the same are disclosed. Furthermore, a method
of bit-by-bit erasing, in addition to page erasing, of a plurality of cells of
two or more is disclosed through the application of a positive voltage forced onto
the control gate of the unselected cell. Thus, by providing the bit-by-bit erasing
flexibility, the bit alterability is enhanced. The MSG is formed with N+1 stacked
gates comprising floating gates and control gates, separated by N select gates,
all sharing the same source/drain between a pair of bit lines. The programming,
that is, writing of the plurality of N+1 bits is accomplished also bit by bit where
the programmed bits are selected by word line, bit line and control gate. The read
operation is similar to the write operation. Thus, it is disclosed here that a
plurality of N+1 bits or cells, where N is any integer, can be formed between two
bit lines and along the same word line and also be programmed with enhanced bit alterability.