A Simple interpolation method for the carrier mobility in Trigate and gate-all-around silicon NWFETs from a non-equilibrium Green’s Functions perspective

Zaiping Zeng (1) , Francois Triozon (2, 1) , Yann-Michel Niquet (3) , Sylvain Barraud (2, 1)

1 UGA [2016-2019] - Université Grenoble Alpes [2016-2019]
2 CEA-LETI - Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information
3 LSIM - Laboratory of Atomistic Simulation

In the non-equilibrium Green's Functions (NEGF) framework, quantum calculations on the electron and hole mobilities have been performed on gate-all-around and Trigate rectangular silicon nanowire (SiNW) devices with leading dimension up to 50 nm. We find that when NW width or height falls in the sub-10 nm range, nearest neighbouring corner channels tend to merge and form "side channels" with much lower mobilities. The contribution from these "side channels" remains significant even at large effective channel width, causing a rather slow convergence towards the limit of thin film device. On top of these numerical results, a simple but effective interpolation model for the size-dependent modulation of carrier mobility in rectangular SiNW devices has been derived, which only requires the mobilities of square NW devices and of the limiting thin film devices as inputs. These mobilities can be obtained by combining contributions from partial mobilities limited by various common scattering mechanisms (phonons, surface roughness and remote Coulomb scattering). We provide these partial mobilities by NEGF calculations for reference devices with NW sizes or film thickness in sub-10 nm range. Empirical models for the carrier density dependent partial mobilities have been further developed. Finally, comparison with experimental data has been made to validate the derived mobility interpolation model and excellent agreement has been achieved.

Domaines: Physique [physics]; Matière Condensée [cond-mat]

Zaiping Zeng, Francois Triozon, Yann-Michel Niquet, Sylvain Barraud. A Simple interpolation method for the carrier mobility in Trigate and gate-all-around silicon NWFETs from a non-equilibrium Green’s Functions perspective. 2019. ⟨cea-01973715v1⟩