Improved Operation Characteristics for Nonvolatile Charge-Trapping Memory Capacitors with High-κ Dielectrics and SiGe Epitaxial Substrates

A novel high-kappa Al2O3/HfO2/Al2O3 nanolaminate charge trapping memory capacitor structure based on SiGe substrates with low interface densities is successfully fabricated and investigated. The memory capacitor exhibits excellent program-erasable characteristics. A large memory window of similar to 4 V, a small leakage current density of similar to 2 x 10(-6) Acm(-2) at a gate voltage of 7 V, a high charge trapping density of 1.42 x 10(13) cm(-2) at a working voltage of +/- 10V and good retention characteristics are observed. Furthermore, the programming (Delta V-FB = 2.8V at 10 V for 10 mu s) and erasing speeds (Delta V-FB = -1.7V at -10V for 10 mu s) of the fabricated capacitor based on SiGe substrates are significantly improved as compared with counterparts reported earlier. It is concluded that the high-kappa Al2O3/HfO2/Al2O3 nanolaminate charge trapping capacitor structure based on SiGe substrates is a promising candidate for future nano-scaled nonvolatile flash memory applications.