3-levels-stacked InxGa1-xAs Multi-Bridge Channel Field-Effect-Transistors

초록

The gate-all-around (GAA) multi-bridge channel FET (MBCFET) architecture is believed to be the final evolutionary step for Moore's law. To achieve a sufficient amount of I-ON at low V-DD, it would be essential to use high-mobility channel materials including III-Vs and Ge. In particular, indium- rich InxGa1-xAs material systems with x in excess of 0.53 are regarded as a promising channel material for future CMOS logic and memory applications due to their exceptional electron carrier transport properties, including a very high injection velocity (vinj). In this talk, we present 3-levels-stacked In0.53Ga0.47As GAA MBCFETs with selectively regrown n+ In0.53Ga0.47As source/drain contacts by MOCVD. For a device fabrication, we use an epitaxy wafer with an In0.53Ga0.47As/In0.52Al0.48As multi-superlattice structure, and vertically stacked channels are electrically connected to selectively regrown n+ In0.53Ga0.47As contacts in the source/drain region. In0.52Al0.48As sacrificial layers are etched isotropically with an HCl-based etchant, releasing the In0.53Ga0.47As nanosheet (NS) channel layers. The device adopts an ALD-grown high-k dielectric layer of HfO2 and a TiN metal gate to implement the GAA structure. The fabricated MBCFETs with L-g = 130 nm, W-NS = 300 nm and t(NS) = 15 nm exhibit a combination of I-ON = 2.2 mA/square m and g(m_max) = 5.7 mS/square m at V-DS = 0.8 V, making efficient use of each multi-bridge channel along the S/D and gate width directions.