Secondary ion mass spectrometry of deep trench capacitors in dynamic random access memory

Secondary ion mass spectrometry (SIMS) supported the development of deep trench capacitors in dynamic random access memory. SIMS is done efficiently by analyzing thousands of cells in parallel and the approach described in this article is scaleable to the multi-Gbit generation. By projecting out fundamental values using geometrical formalisms, the behavior of contaminants and dopants in sub-micrometer geometries is understood without the need for small-area measurements. This array-profiling approach is used to quantify and partition halogen, alkali, and transition-metal contaminants among deep trench and other processing sectors. The deposition of self-limiting layers of arsenic during polysilicon fill of the deep trench is explored in detail. The doping of the trench sidewalls, either through angle ion implants or by drive in of doped-glass deposition,. is quantified. (C) 1999 American Vacuum Society. [S0734-2101(99)19204-2].