Metal-insulator-metal capacitors with ALD grown SrTiO3: Influence of Pt electrodes

Abstract

Metal-Insulator-metal (MIM) capacitors with atomic layer deposited (ALD) single SrTiO3 dielectric have been investigated in this work. Structural and electrical properties were studied after the formation of the MIM stack consisting of the platinum (Pt) bottom electrode, 50 nm SrTiO3 layer and the top Pt electrode. The as deposited films were amorphous and had a dielectric constant of ∼ 10, whereas the annealing of the samples in the nitrogen (N2) or oxygen (O2) atmosphere at 550-600 °C led to the crystallization of the SrTiO3 and therefore to the increased dielectric constant of ∼ 85. In addition, the electrical results revealed that the combination of SrTiO3 with the high work function electrode like Pt, provided better leakage current performance in comparison with TiN/ SrTiO3 stacks. The values as low as ∼ 10-7 A/cm2 at 2 V were observed for both in N2 or O2 annealed SrTiO3 layers. On the other hand, the samples annealed in O2 atmosphere at 600 °C possessed lower capacitance-voltage nonlinearity coefficients (-645 ppm/V2) than the ones for N2 annealed samples (-2700 ppm/V 2). © Published under licence by IOP Publishing Ltd.