Atomic layer deposition of high capacitance density Ta2O5-ZrO2 based dielectrics for metal-insulator-metal structures

作者：Jogi Indrek^*; Kukli Kaupo; Ritala Mikko; Leskela Markku; Aarik Jaan; Aidla Aleks; Lu Jun

来源：Microelectronic Engineering, 2010, 87(2): 144-149.

DOI：10.1016/j.mee.2009.06.032

• Nanolaminates
• Atomic layer deposition
• High-k dielectric

We have investigated electrical properties of laminated atomic layer deposited films: ZrO2-Ta2O5, ZrO2-Nb2O5-Ta2O5, ZrO2-TaxNb1-xO5 and Ta2O5-ZrxNbyOz. Even though the capacitances of laminates were often higher compared to films of constituent materials with similar thickness, considerably higher charge storage factors, Q were achieved only when tetragonal ZrO2 was stabilized in ZrO2-Ta2O5 laminate and when the laminate thickness exceeded 50 rim. The decreased Q values in the case of most laminates were the result of increased leakage currents. In the case of thinner films only Ta2O5-ZrxNbyOz, stack possessed capacitance density and Q value higher than reference HfO2. Concerning the conduction mechanisms, in the case of thinner films, the Ta2O5 or TaxNb1-xO5 apparently controlled the leakage either by Richardson-Schottky emission or Poole-Frenkel effect.

• 出版日期2010-2