NON-VOLATILE MEMORY DEVICE AND METHODS OF FORMING AND OPERATING THE SAME

摘要

An NVM(non-volatile memory) device is provided to avoid writing/reading error while improving integration of a cell by making one memory transistor include sidewall select gates covering both sidewalls of a floating gate while the floating gate and a control gate are stacked. A first gate insulation layer(5) is formed on a semiconductor substrate(1). A floating gate(7a) is formed on the first gate insulation layer. The upper surface and both lateral surfaces of the floating gate are covered with a second gate insulation layer. The second gate insulation layer(9) formed on one sidewall of the floating gate is covered with a first sidewall select gate(11a). The second gate insulation layer formed on the other sidewall of the floating gate is covered with a second sidewall select gate(11b). An intergate dielectric(16) is formed on the first sidewall select gate, the second gate insulation layer and the second sidewall select gate. A control gate exposes the intergate dielectric formed on the first and the second sidewall select gates, overlapping the floating gate on the intergate dielectric. A source region(23a) is formed in the semiconductor substrate that is adjacent to the first sidewall select gate and is separated from the floating gate. A drain region(23b) is formed in the semiconductor substrate that is adjacent to the second sidewall select gate and is separated from the floating gate. The first gate insulation layer under the first and the second sidewall select gates is thicker than the first gate insulation layer under the floating gate.