Method Of Making Embedded Memory Device With Silicon-On-Insulator Substrate

A method of forming a semiconductor device where memory cells and some logic devices are formed on bulk silicon while other logic devices are formed on a thin silicon layer over insulation over the bulk silicon of the same substrate. The memory cell stacks, select gate poly, and source regions for the memory devices are formed in the memory area before the logic devices are formed in the logic areas. The various oxide, nitride and poly layers used to form the gate stacks in the memory area are formed in the logic areas as well. Only after the memory cell stacks and select gate poly are formed, and the memory area protected by one or more protective layers, are the oxide, nitride and poly layers used to form the memory cell stacks removed from the logic areas, and the logic devices are then formed.