Fully integrated 512 Mb DRAMs with hemispherical grain (HSG) merged Al2O3/HfO2 (AHO) cylinder capacitor were successfully developed for the first time. Highly manufacturable reverse HSG one cylinder storage node (RHOCS) technique and AHO capacitor process were successfully implemented. Cell capacitance of HSG-merged-AHO capacitor has improved up to 24% compared to that of ALO capacitor without any capacitor-related leakage current failure. 512 Mb DRAMs with HSG-merged-AHO capacitors shows improved retention characteristics and excellent test yield due to improved cell capacitance. (c) 2006 Elsevier Ltd. All rights reserved.