Interfacial layer growth condition dependent carrier transport mechanisms in HfO2/SiO2 gate stacks

The temperature and field dependent leakage current in HfO2/SiO2 gate stack for in situ steam grown and chemical interfacial layers (ILs) are studied in the temperature range of 20 degrees C to 105 degrees C. Poole-Frenkel mechanism in high field whereas Ohmic conduction in low field region are dominant for both devices. Leakage current decreases whereas both trap energy level (phi(t)) and activation energy (E-a) increase for chemically grown IL devices. The trap level energy, (phi(t)) similar to 0.2 eV, indicates that doubly charged oxygen vacancies (V2-) are the active electron traps which contribute to the leakage current in these gate stacks. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4726186]