Optimization of High-k films on Si Substrate : fabrication and characterization

In the present diploma project work, metal oxide semiconductor capacitors were fabricated on Silicon substrate. The oxide layer was formed by atomic layer deposition of high permittivity materials, HfO2 and Al2O3. The high-k films were grown using 65 ALD cycles at various deposition temperatures. For each deposition temperature, a series of samples were prepared using different precursor pulse lengths. The effect of growth conditions were investigated by current-voltage and capacitance-voltage characterization on 42 samples. C-V and I-V curves of different devices were found to be highly influenced by traps at high-k/Si interface and border traps within the oxide layer. HfO2 film deposited at 250 °C substrate temperature, using 450 ms Hf-precursor pulse length and Al2O3 film deposited at 350 °C were shown to have the low density of interface traps and CV hysteresis