Passivation of Ge surface treated with trimethylaluminum and investigation of electrical properties of HfTiO/Ge gate stacks

In the current work, in situ surface passivation Ge substrate by using trimethylaluminum (TMA) prior to HfTiO films deposition and electrical properties of HfTiO/Ge gate stacks have been investigated by X-ray photoelectron spectroscopy (XPS) and electrical measurements systematically. Based on analysis from XPS measurements, it has been confirmed that the interfacial layer of HfTiO/Ge gate stack has been suppressed effectively after 20 half-ALD cycles TMA pretreatment. Electrical properties of metal-oxide-semiconductor (MOS) capacitor based on HfTiO gate dielectrics have shown that the MOS capacitor with 20 cycles TMA cleaning exhibits the lowest interface state density (similar to 7.56 eV(-1) cm(-2)) and the smallest leakage current (similar to 2.67 x 10(-5) A/cm(2)). Correspondingly, the leakage current conduction mechanisms for MOS capacitor device with 20 cycles TMA cleaning also have been discussed in detail. (c) 2017 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.