Suppression of the Drift Field in the p-Type Quasineutral Region of a Semiconductor p–n Junction

An improved analytical model of the drift field suppressed by the Dember field due to ambipolar diffusion in the p-type quasineutral region (p-QNR) of a forward silicon p–n junction at low injection levels is presented with a good fit to the numerical simulation results. Considering ambipolar transport of both carriers, the diode current in the p-QNR is found to consist of a minority-electron diffusion-current component and majority-hole drift- and diffusion-current components, and the Dember field plays a dominant role in balancing all the components mentioned above to keep the current constant. The analytical model is beneficial to completely understand ambipolar current transport mechanisms in semiconductor p–n junction devices.