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

A novel high-\kappa Al_2O_3/HfO_2/Al_2O_3 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 \sim 4 V, a small leakage current density of \sim 2 \times 10^-6 Acm^-2 at a gate voltage of 7 V, a high charge trapping density of 1.42\times 10^13 cm^-2 at a working voltage of \pm10 V and good retention characteristics are observed. Furthermore, the programming (\Delta V_\rm FB=2.8 V at 10 V for 10 μs) and erasing speeds (\Delta V_\rm FB=-1.7 V at -10 V for 10 μs) of the fabricated capacitor based on SiGe substrates are significantly improved as compared with counterparts reported earlier. It is concluded that the high-\kappa Al_2O_3/HfO_2/Al_2O_3 nanolaminate charge trapping capacitor structure based on SiGe substrates is a promising candidate for future nano-scaled nonvolatile flash memory applications.