Heat generation approximation in modulation-doped field-effect transistorsby the energy relaxation between carriers and phonons

A combination of the nonlinear charge-control model, rate balance equations , and electron-phonon scattering is used to simulate the hot-electron trans port and heat generation problem of modulation-doped field-effect transisto rs. Based on the present model, the trend of high-field transport can be we ll demonstrated. In addition, the heat generation inside the channel can al so be estimated by the energy flux balance equation with the energy relaxat ion rate formulated by polar-optical phonon scattering mechanism. Scaling d own the gate length to submicron range, more heat power is generated inside the channel. However, the heat generation ratio reveals that hot electrons carry over half of the energy density gained from the applied electric fie ld directly into drain region. For 0.1 mu m gate length, more than 90% ener gy density is achieved. By reducing the gate length into the deep submicron range, the thermal impact on the drain side becomes more serious and compl icated than the one found inside the channel. (C) 2000 American Institute o f Physics. [S0021-8979(00)05417-7].