Significance of L-valley charges and a method to include it in electrostatic model of III-V GAA FETs

Small
$\Gamma-L$
valley energy offset in III-V materials such as GaAs is shown to improve the transistor performance, overcoming the density of states bottleneck while maintaining high injection velocity. Existing compact models for III-V channel transistors only account for the dominant
$\Gamma$
-valley charges. This underestimates the transistors circuit performance. In this work, for the first time, a compact model is introduced to include the
$L$
-valley charges in III-V GAA transistor electrostatics. The quantum mechanical effects arising because of the highly confined GAA geometry is also included. The proposed model is compared with the data obtained from 2D Poisson-Schrodinger solver for different III-V channel materials and dimensions and found to be in excellent agreement.