| 摘要 |
A memory cell structure for a memory device is provided, the memory cell structure comprising a read transistor having a floating gate node, a tunnelling capacitor, and a coupling capacitor stack. The tunnelling capacitor is connected to the floating gate node and has a first programming terminal, whilst the coupling capacitor stack is connected to the floating gate node and has a second programming terminal. The coupling capacitor stack comprises at least two coupling capacitors arranged in series between the floating gate node and the second programming terminal, with the coupling capacitor stack having a larger capacitance than the tunnelling capacitor. During a programming operation, a voltage difference is established between the first programming terminal and the second programming terminal to cause charge tunnelling to occur through the tunnelling capacitor, such that after the programming operation a charge is stored in the floating gate node. During a read operation, the read transistor is activated to produce an output signal indicative of the charge stored in the floating gate node. Such a memory cell structure is efficient in terms of area, and can be manufactured using standard CMOS logic manufacturing processes, thereby avoiding some of the complexities involved in the production of more conventional EEPROM and Flash memory devices.
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