Abstract

GdxSc1-xOy and Sc1-xAlxOy (0.2 <= x <= 0.5) were investigated as potential intergate dielectric (IGD) candidates for hybrid floating gate (HFG) applications. In HFG the poly-Si FG is replaced by a Si/TiN stack. An excellent program/erase window of similar to 14 V and good retention performance are obtained for Sc1-xAlxOy, which has a k-value of similar to 14. GdxSc1-xOy displays a higher k of similar to 21, but its large leakage current and low breakdown field of less than 4 MV/cm make this material incompatible with our applications. The main differences between both scandates concern to their crystallization and thermal stability. Indeed, for similar compositions and thermal treatments, as required by the fabrication process of the devices (800-1000 degrees C), GdxSc1-xOy tend to be more crystalline and with an enhanced Ti, N and Si diffusion into the IGD as compared to Sc1-xAlxOy. (C) 2013 Elsevier B.V. All rights reserved.