| 摘要 |
A programmable memory transistor (PMT) comprising an IGFET and a coupling capacitor in a semiconductor substrate. The IGFET comprises source and drain regions, a channel therebetween, a gate insulator overlying the channel, and a first floating gate over the gate insulator. The capacitor comprises a lightly-doped well of a first conductivity type, heavily-doped contact and injecting diffusions of opposite conductivity types in the lightly-doped well, a control gate insulator overlying a surface region of the lightly-doped well between the contact and injecting diffusions, a second floating gate on the control gate insulator, and a conductor contacting the lightly-doped well through the contact and injecting diffusions. The first and second floating gates are preferably patterned from a single polysilicon layer, such that the second floating gate is capacitively coupled to the lightly-doped well, and the latter defines a control gate for the first floating gate.
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