Current source component with process tracking characteristics for compact programmed Vt distribution of flash EPROM

摘要

A new structure and method with a process tracking current source component to program a flash EPROM memory is proposed. By applying a current source which varies not only with the process variation but also with the source bias of the cell being programmed, a self-convergent and high-efficiency programming can be achieved. This process tracking current source component provides less current for cells with higher erased Vt and larger current for cells with lower erased Vt.A circuit for programming a floating gate transistor includes a current source component. The current source component couples in series between the floating gate transistor and an electrical sink during a programming interval. The current source component includes an electrical characteristic substantially matching the electrical characteristic of the floating gate transistor.An integrated circuit memory module on a semiconductor substrate is disclosed. The integrated circuit memory module includes: an array of floating gate memory cells, decoders, and a plurality of current source components. The array of floating gate memory cells is arranged in M rows and N columns. The decoders couple to the M rows and N columns of memory cells to provide for reading and programming floating gate memory cells within a selected one of the M rows of the memory array. The plurality of current source components each couple in series between an electrical sink and a corresponding one of the floating gate memory cells within the selected one of the M rows during a programming interval. Each of the plurality of current source components includes an electrical characteristic substantially matching the electrical characteristic of the corresponding one of the floating gate memory cells to be programmed.