A novel approach to generate self-aligned Ge/SiO2/SiGe gate-stacking structures in a single fabrication step

We demonstrated a novel, self-aligned gate-stack heterostructure of Ge-quantum dot (QD)/SiO₂/SiGe-shell on Si with superior interfacial properties in a single step of selective oxidation of a SiGe pillar over a Si₃N₄ buffer layer on Si substrate. Ge metal-oxide-semiconductor (MOS) capacitors exhibit a quite low interface trap density on the order of 10¹¹ cm^-2eV^-1, and Ge n-MOSFETs show good turn on and off features with a subthreshld slope of 175 mV/dec and I_on/I_off > 10⁶.