Novel Al/sub 2/O/sub 3/ capacitor for high density DRAMs

Abstract

A poly-Si/Al/sub 2/O/sub 3//poly-Si capacitor is developed for the simple integration of 256 Mb DRAM and beyond. The oxide equivalent thickness (T/sub 0xeq/) of the Al/sub 2/O/sub 3/ capacitor was achieved as small as 28 nm, which is about 1.7 times smaller than that of advanced NO capacitor. Especially, the pre-treatment before the deposition of Al/sub 2/O/sub 3/ film plays a crucial role for stable device performance. Moreover, one of the distinguished characteristics of the Al/sub 2/O/sub 3/ capacitor is that the capacitance was even enhanced by performing the conventional DRAM processes, including the high temperature planarization method known as BPSG flow, without degrading the leakage characteristics.