Development of 3D on-chip capacitor based on high-κ dielectric

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Popis
The high-κ dielectric materials are commonly used in microelectronic components due to technological necessity of increasing the permittivity of dielectric layers. The thickness of the layer is crucial parameter of this technology because it has significant influence on the dielectric properties, capacitance density, leakage current density-voltage (J-V), and capacitance density-voltage (C-V) characteristics.
Among metal oxide compounds, HfO2 and Al2O3 have been widely studied due to their good thermodynamic stability in contact with silicon. The devices have been fabricated by ALD processes on Si wafer. Properties of HfO2/Al2O3-based dielectric as on-chip MIS capacitors were studied. The capacitance density, C-V and impedance characteristics, and leakage current were measured. The equivalent dielectric constant, capacitance density, breakdown voltage and leakage current are studied on stacks (HfO2/Al2O3) in ration of 1:1. The experimental results indicate very good leakage current and good breakdown voltage. The trenches with aspect ratio 1:28 were developed to form 3D structure for future increasing capacitance density on square centimetre. Top electrode metallization using several different techniques to fill in the trenches was also studied.
Klíčová slova
ALD
capacitance density
HfO2/Al2O3
dielectric
breakdown voltage
C-V
leakage