Single SrTiO 3 and Al 2O 3/SrTiO 3/Al 2O 3 based MIM capacitors: Impact of the bottom electrode material

Abstract

Metal–Insulator–Metal (MIM) capacitors with atomic layer deposited (ALD) single SrTiO 3 dielectric and Al 2O 3/SrTiO 3/Al 2O 3 multilayer dielectric have been deposited on TaN and TiN bottom electrodes. The MIM stacks have been analyzed and compared in terms of electrical and structural properties. The results indicate that MIMs with multilayer dielectrics provide better leakage current performance than the ones with single dielectrics while capacitance density is decreased. Additional Al 2O 3 layers prevented the crystallization of SrTiO 3 in the multilayer dielectric stack. The decreased capacitance density in MIMs with multilayer dielectric is attributed to the amorphous structure of SrTiO 3 and the series capacitance of top and bottom Al 2O 3 layers. Furthermore, MIM capacitors with single SrTiO 3 dielectric layer on TiN electrodes indicated better capacitance density compared to the one with TaN electrodes. The lower capacitance density of the single SrTiO 3 dielectric on TaN electrodes is correlated to the interfacial layer formation between SrTiO 3 and TaN electrodes.