Two-phase programming of a flash memory

A memory device comprising:

• (a) at least one cell;
• and
• (b) a controller operative:
• (i) to place one of said at least one cell in a first state that is indicative of a datum, and
• (ii) to place said one cell in a second state that is indicative of said datum, said second state having a longer data retention time than said first state.

A method of storing a datum in a memory that includes a plurality of cells, the method comprising the steps of:

• (a) placing a first cell of the memory in a first state that is indicative of the datum;
• and
• (b) placing a second cell of the memory in a second state that is indicative of the datum, said second state having a longer data retention time than said first state;
• wherein said first cell and said second cell then store an identical number of bits.

A memory device comprising:

• (a) an array of cells;
• and
• (b) a controller operative:
• (i) to place a first of said cells in a first state that is indicative of a datum, and
• (ii) to place a second of said cells in a second state that is indicative of said datum, said second state having a longer data retention time than said first state,
• wherein said first cell and said second cell then store an identical number of bits.

A method of operating a memory that includes a plurality of cells, comprising the steps of:

• (a) for each of at least one of the cells:
• (i) comparing a threshold voltage of said each cell to a first reference voltage that is indicative of a certain bit pattern, and
• (ii) comparing said threshold voltage of said each cell to a second reference voltage that is greater than said first reference voltage and that also is indicative of said bit pattern;
• and
• (b) for each said at least one cell, if said comparing shows that said threshold voltage of said each cell is between said first reference voltage and said second reference voltage:
• applying at least one voltage pulse to said each cell until said threshold voltage of said each cell is greater than said second reference voltage.

A memory device comprising:

• (a) at least one cell;
• and
• (b) a controller operative, for each said at least one cell for which a comparison of a threshold voltage of said each cell to a first reference voltage that is indicative of a certain bit pattern and to a second reference voltage that is indicative of said bit pattern shows that said threshold voltage of said each cell is between said first reference voltage and said second reference voltage:
• to apply at least one voltage pulse to said each cell until said threshold voltage of said each cell is greater than said second reference voltage.

A method of operating a memory that includes a plurality of cells, comprising the steps of:

• (a) for each of at least one of the cells:
• (i) comparing a threshold voltage of said each cell to a first reference voltage that is indicative of a certain bit pattern, and
• (ii) comparing said threshold voltage of said each cell to a second reference voltage that is greater than said first reference voltage and that also is indicative of said bit pattern;
• and
• (b) for each said at least one cell, if said comparing shows that said threshold voltage of said each cell is between said first reference voltage and said second reference voltage:
• applying at least one voltage pulse to a corresponding other cell until a threshold voltage of said corresponding other cell is greater than said second reference voltage.

A memory device comprising:

• (a) an array of cells;
• and
• (b) a controller operative, for each said cell of said array for which a comparison of a threshold voltage of said each cell to a first reference voltage that is indicative of a certain bit pattern and to a second reference voltage that is indicative of said bit pattern shows that said threshold voltage of said each cell is between said first reference voltage and said second reference voltage:
• to apply at least one voltage pulse to a corresponding other cell of said array until a threshold voltage of said corresponding other cell is greater than said second reference voltage.