Hamburg 2001 – scientific programme

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SYOD: Oxidische Dünnschichten

SYOD 1: Oxidische Dünnschichten

SYOD 1.5: Invited Talk

Thursday, March 29, 2001, 16:30–17:00, J

Etching of refractory metal electrodes and complex oxides — •Hermann Kohlstedt, Stefan Schneider, and Rainer Waser — Forschungszentrum Jülich, Institut für Festkörperforschung

High-k dielectric perovskite materials (Ba_xSr_1−xTiO₃ for DRAM capacitors along with new electrode materials, have been under development. Scaling of devices is necessary to increase the memory density, but cannot address the capacitance limitation. Some of the perovskite materials are ferroelectric (PbZr_xTi_1−xO₃, SrBi₂Ta₂O₉, PbTiO₃).This opens the possibility for non-volatile memories and low power consumption. For the integration of perovskites refractory metals such as platinum, iridium, and ruthenium are required which can withstand high process temperatures and high oxygen pressures during film growth or post annealing processes. Therefore the integration of complex oxides and refractory metal electrodes into CMOS processing this a challenge. To systematically investigate possible reactive etch process parameter regions (for Pt), characterized by volatile etch products, we used a reactive ion beam etching (RIBE) tool with a filament free ICP (Inductively Coupled Plasma) source, that gives us exact control over the beam energy and the current density, and allows to use reactive gases. The results show a significant reactive etch component in comparison to simple Ar sputter processes by using Chlorine and high substrate temperatures of 300 C. Possible etch mechanism for Pt with different gas mixtures will be discussed.