Method of fabricating and operating single polysilicon flash EEPROM with low positive programming and erasing voltage and small cell size
 A single polysilicon memory cell (10) provides a positive low programming and erase voltage together with a small cell size and includes P substrate (12) and P-well (14) formed within P substrate (12). NMOS transistor (16) is formed within P-well (14). N.sup.+ control gate (26) is formed in P-well (14) and includes punch-through implant region (26). NMOS transistor (16) and N.sup.+ control gate (26) have in common electrically isolated polysilicon gate (22, 32) for operating as a floating gate in common with NMOS transistor (16) and N.sup.+ control gate (26). N.sup.+ control gate (26) includes P-channel punch-through implant (34) for increasing the capacitive coupling ratio. This improves programming and erasing efficiency within single polysilicon memory cell (10). 
Texas Instruments Incorporated
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G11C H01L H01L
additional inventional inventional
Chi-Chien William R.
Ho McKee