Capacitance-voltage characteristics of sub-nanometric Al2O3 / TiO2 laminates: dielectric and interface charge densities

Advanced amorphous sub-nanometric laminates based on TiO2 and Al2O3 were deposited by atomic layer deposition at low temperature. Low densities of 'slow' and 'fast' interface states are achieved with values of 3.96 · 1010 cm−2 and 4.85 · 10−9 eV−1 cm−2, respectively, by using a 40 nm laminate constituted of 0.7 nm TiO2 and 0.8 nm Al2O3. The sub-nanometric laminate shows a low hysteresis width of 20 mV due to the low oxide charge density of about 3.72 · 1011 cm−2. Interestingly, such properties are required for stable and reliable performance of MOS capacitors and transistor operation. Thus, decreasing the individual layer thickness to the sub-nanometric range and combining two dielectric materials with oppositely charged defects may play a major role in the electrical response, highly promising for the application in future micro and nano-electronics applications.