| 摘要 |
A semiconductor memory device having a memory cell region and a peripheral circuit region, and a method of manufacturing such a semiconductor memory device, are proposed, in which trench grooves are formed to be shallow in the memory cell region in order to improve the yield, and trench grooves are formed to be deep in the high voltage transistor region of the peripheral circuit region, in particular in a high voltage transistor region thereof, in order to improve the element isolation withstand voltage. A plurality of memory cell transistors having an ONO layer 15 serving as a charge accumulating insulating layer are provided in the memory cell region, where element isolation grooves 6 for these memory cell transistors are narrow and shallow. Two types of transistors, one for high voltage and the other for low voltage, having gate insulating layers 16 or 17 , which are different from the ONO layer 15 in the memory cell region, are provided in the peripheral circuit region, where at least element isolation grooves 23 for high voltage transistors are wide and deep. In this way, it is possible to improve the degree of integration and yield in the memory cell region, and secure withstand voltage in the peripheral circuit region.
|
