Patent ID: 7785906

Claim:
A method for testing a semiconductor device, comprising: providing a test structure comprising a MOS transistor and a floating gate transistor; applying voltages to the MOS transistor which are sufficient to activate a functional MOS transistor; applying voltages to the MOS transistor which are not sufficient to activate a functional MOS transistor; applying voltages to the floating gate transistor which are not sufficient to activate a functional unprogrammed floating gate transistor; then applying voltages to the floating gate transistor which are sufficient to program a functional floating gate transistor; then applying voltages to the floating gate transistor which are sufficient to activate a functional programmed floating gate transistor; and failing the semiconductor device for residual polysilicon across at least one of the source and drain of the floating gate transistor, if: a) the MOS transistor activates during the application of the voltages sufficient to activate a functional MOS transistor; or the MOS transistor does not activate during the application of the voltages which are not sufficient to activate a functional MOS transistor; and b) a current across a channel of the floating gate transistor is less than about 1.0 microamp (μA) during the application of voltages which are not sufficient to activate a functional unprogrammed floating gate transistor; a current across a channel of the floating gate transistor is more than about 200 μA during the application of voltages which are not sufficient to activate a function unprogrammed floating gate transistor; a current across a channel of the floating gate transistor is less than about 10 μA during the application of voltages which are sufficient to activate a functional programmed floating gate transistor; or a current across a channel of the floating gate transistor is more than about 100 μA during the application of voltages which are sufficient to activate a functional programmed floating gate transistor.