A process for fabricating a three-dimensional NOR memory string of storage transistors implements a channel-last fabrication process with channel replacement using silicon germanium (SiGe). In particular, the process uses silicon germanium as a sacrificial layer, to be replaced with the channel material after the charge-storage layer of the storage transistors is formed. In this manner, the channel region is prevented from experiencing excessive high-temperature processing steps, such as during the annealing of the charge-storage layer.