Nanoscale Reconfigurable Si Transistors: From Wires to Sheets and Unto Multi-Wire Channels

In this work, bottom-up Al-Si-Al nanowire (NW) heterostructures are presented, which act as a prototype vehicle toward top-down fabricated nanosheet (NS) and multi-wire (MW) reconfigurable field-effect transistors (RFETs). Evaluating the key parameters of these transistors regarding the on- and off-currents as well as threshold voltages for n- and p-type operation exhibit a high degree of symmetry. Most notably also a low device-to-device variability is achieved. In this respect, the investigated Al-Si material system reveals its relevance for reconfigurable logic cells obtained from Si NSs. To show the versatility of the proposed devices, this work reports on a combinational wired-AND gate obtained from a multi-gate RFET. Additionally, up-scaling the current is achieved by realizing a MW RFET without compromising reconfigurability. The Al-Si-Al platform has substantial potential to enable complex adaptive and self-learning combinational and sequential circuits with energy efficient and small footprint computing paradigms as well as for native components for hardware security circuits. The applicability of monolithic Al-Si heterojunctions for reconfigurable transistors is demonstrated on bottom-up grown Si nanowires. To enable multi-gate and multi-channel devices for combinational wired-logic and for efficient current up-scaling a transfer to SOI technology is reported. The proposed Al-Si platform might be promising for diverse adaptive self-learning computing as well as new approaches for hardware security solutions.image