Self-organized gate stack of Ge nanosphere/SiO2/Si1-xGex enables Ge-based monolithically-integrated electronics and photonics on Si platform

摘要

We report the first-of-its-kind, self-organized gate stack of Ge nanosphere (NP) gate/SiO₂/Si_1-xGe_x channel fabricated in a single oxidation step. Process-controlled tunability of the Ge NP size (5-90nm), SiO₂ thickness (2-4nm), and Ge content (x = 0.65-0.85) and strain engineering (ε_comp = 1-3%) of the Si_1-xGe_x are achieved. We demonstrated Ge junctionless (JL) n-FETs and photoMOSFETs (PTs) as amplifier and photodetector, respectively, for Ge receivers. L_G of 75nm JL n-FETs feature I_ON/I_OFF > 5×10^{8, I_ON > 500μA/μm at V_DS = 1V, T= 80K. Ge-PTs exhibit superior photoresponsivity >1,000A/W and current gain linearity ranging from nW-mW for 850nm illumination. Size-tunable photo-luminescence (PL) of 300-1600nm (NUV-NIR) are observed on 5-100nm Ge NPs. Our gate stack of Ge NP/SiO₂/Si_1-xGe_x enables a practically achievable building block for monolithically-integrated Ge electronic and photonic ICs (EPICs) on Si.}