Regensburg 2010 – wissenschaftliches Programm
DF 7.6: Vortrag
Dienstag, 23. März 2010, 15:40–16:00, H11
CaTiO3 as a high-k dielectric in thin MIM Capacitor stacks — •Andreas Krause1, Walter M. Weber1, Andreas Jahn2, Ulrich Merkel2, Matthias Albert2, Uwe Schroeder1, Johann W. Bartha2, and Thomas Mikolajick1 — 1namlab gGmbh, D-01187 Dresden — 2Institut fuer Halbleiter- und Mikroelektronik IHM, TU Dresden
With the further increase in integration density of microelectronics, ordinary SiO2-based dielectrics reach their limits as leakage currents increase significantly. Therefore, dielectric materials are required that combine a high dielectric constant (k) and low leakage currents. Metal Insulator Metal (MIM) stacks with the perovskite calcium titantate (CaTiO3) as a high-k oxide were sputter deposited with variing thicknesses and deposition temperatures. As electrodes, different work function materials were used: Pt, Ru, TaSiN, TiN. Optimizing the roughness and deposition parameters of the electrodes, a k-value of 51 is reached with a capacitance equivalent thickness targeting 1nm. The leakage currents for 15 nm thick CaTiO3 films are about 1 · 10−7 A/cm2 at 1 V, which is in agreement with the ITRS roadmap of 2013. The morphology was studied with atomic force microscopy and scanning electron microscopy. Capacitor-voltage measurements were performed to extract the k-value. In addition, the crystallinity of the oxide and metal electrode was investigated with variable temperature x-ray defraction measurements, showing clearly the transition from the amorphous to the crystal state in dependence of the temperature.