INTEGRATED BARRIER PLUG FILL SCHEMES FOR HIGH-ASPECT-RATIO GB DRAM CONTACT METALLIZATION/

New contact fill integration schemes were developed for high aspect ra tio Gb DRAM contact metallization. Integration schemes for both tungst en-plug contacts and aluminum-plug contacts were studied. For tungsten -plug contacts, various types of titanium liners and titanium nitride barriers were investigated and evaluated. These included collimated PV D (physical vapor deposition) titanium, ion metal plasma (IMP) titaniu m, and CVD (chemical vapor deposition) titanium liners; plasma enhance d CVD (PECVD) titanium nitride and plasma enhanced MOCVD (ECVD) titani um nitride barriers. The electrical results of 0.3 mu m, 5:1 aspect ra tio (AR) contact structures processed with a TiCl4-based CVD titanium liner and plasma enhanced CVD titanium nitride barrier show the lowest and the most tightly distributed contact parametrics. This is attribu ted to the conformal nature of the CVD process. In addition, the high titanium-deposition temperature, which leads to a simultaneous titaniu m silicide formation during the CVD titanium deposition process, may a lso have attribution to the low contact resistance and diode leakage o btained. In the case of aluminum-plug contacts, two different types of titanium nitride barriers (ECVD titanium nitride vs. silane-treated M OCVD titanium nitride) were evaluated and both showed comparable conta ct parametrics. (C) 1998 Elsevier Science S.A. All rights reserved.