Fig. 4

Nanoscale-channel transistors with various channel designs. a SOI-FETs with a top gate and bias circuit for I _D-V _G measurements. Different devices have been fabricated, with different doping concentrations and profiles across the channel: b low concentration (N _D ≈ 1 × 10¹⁸ cm⁻³)—single-electron tunneling occurs via individual P-donors (nanowire and stub-shaped channels are illustrated); c high concentration (N _D ≈ 1 × 10¹⁹ cm⁻³)—single-electron tunneling occurs via “clusters” of P-donors