A novel five-channel NMOSFET using selective epitaxial growth (SEG) and lateral solid phase epitaxy (LSPE)

Double gate (DG), gate-all-around (GAA) and vertical transistors were proposed to continue the improvement in device performance down to 20 nm gate length. We report on a novel five-channel (FC) NMOSFET using selective epitaxial growth (SEG) and lateral solid phase epitaxy (LSPE). The FCNMOS is an integration of a conventional bulk NMOS, two vertical NMOS and a gate-all-around NMOS. In the structure, one channel is in the bulk substrate, two channels are in the vertical SEG pillars and two other channels are in the gate-all-around (GAA) structure. The top silicon layer for implementing the GAA structure is obtained by using LSPE with the SEG pillars as the silicon seed. The FC-NMOS has a 3.6 times higher current drive as compared to the conventional bulk NMOS. This makes the FC-NMOS very promising for future ULSI applications.