Method for Forming Single-Level Electrically Erasable and Programmable Read Only Memory Operated in Environment with High/Low-Voltage

摘要

First of all, a semiconductor substrate is provided, and then a first/second wells with a first conductivity are formed therein so as to individually form a first part of the floating gate of single-level EEPROM and a low-voltage device thereon, wherein the first and the second wells are used to separate the high-voltage device, and the depth of the first well is the same as the second well. Furthermore, the high-voltage device and the second part of the floating gate of single-level EEPROM are individually formed on the semiconductor substrate between the first and the second wells, and the control gate of the floating gate of single-level EEPROM is formed in the third well located under the second part of the floating gate of single-level EEPROM, wherein the high-voltage device can be operated in the opposite electric field about 18V, such as−6V˜12V,−12V˜6V,−9V˜9V etc.