Extension of Spherical Harmonic Method to RF Transient Regime

The space and time dependent electron Boltzmann transport equation (BTE) is solved self-consistently with the Poisson and transient hole current-continuity equation. A transient Spherical Harmonic expansion method is used to solve the BTE. By this method we can efficiently solve the BTE in the RF regime to observe how the complete distribution function responds to a rapid transient. Calculations on a BJT, which give the time dependent distribution function over a large energy range 0–3eV, throughout the device, as well as average quantities, require only 40 minutes CPU time on an Alpha workstation.