We compared the electrical properties of HfO 2 , HfO 2 /La 2 O 3 , and La-doped HfO 2 gate insulators deposited on Ge substrate using an atomic layer deposition (ALD) process. TDMAH [tetrakis(dimethylamino)hafnium] and La(iprCp) 3 [tris(isopropyl-cyclopentadienyl) lanthanum] were employed as Hf and La precursors, respectively. Chemical compositions and binding structures were analyzed by X-ray photoelectron spectroscopy (XPS). Electrical properties were evaluated by capacitance-voltage (C-V) and current-voltage (I-V) measurements. We found that incorporation of La 2 O 3 near Ge can enhance the electrical properties of Ge MOS capacitors. The best electrical properties of 50 mV of hysteresis and mid ∼10 12 cm -2 eV -1 range interface states were found for the 400° C-annealed HfO 2 /La 2 O 3 bilayer sample. These values are significantly better than those of ALD HfO 2 gate insulators on Ge. We attribute this to the formation of LaGeO x layers on the Ge surface, which reduces Ge O bonding.
Bibliographical noteFunding Information:
This work was supported by the Industrial Strategic Technology Development Program (10041926, Development of high density plasma technologies for thin film deposition of nanoscale semiconductor and flexible display processing) funded by the Ministry of Knowledge Economy (MKE, Korea) .
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Physics and Astronomy(all)
- Surfaces and Interfaces
- Surfaces, Coatings and Films