Mobile charge and electric field distributions in abrupt PN junctions: An approach with the state variable method
Abstract
Abrupt PN junctions are studied taking the electric field (e) and the potential (p) as state variables. Starting from the Poisson equation, the state variable method determines in closed form the trajectories in the pe plane, from which a quantitative insight of the properties of the space charge layer is obtained as well as the distribution of the mobile charges and the resulting electric field. In the particular case of asymmetrical junctions, the results show that the dominant contribution to the charge density near the metallurgical junction in the lightly doped side is given by the mobile carriers diffused from the highly doped side. In this case the depletion approximation is of poor accuracy in the evaluation of the electric field distribution. A sharp peak of electric field is present at the junction whose maximum value can be orders of magnitude larger than the value predicted by the depletion approximation.
 Publication:

NASA STI/Recon Technical Report N
 Pub Date:
 1990
 Bibcode:
 1990STIN...9212188C
 Keywords:

 Charge Distribution;
 Electric Charge;
 Electric Fields;
 Electric Potential;
 Poisson Equation;
 Doped Crystals;
 PN Junctions;
 Real Variables;
 State Vectors;
 Trajectories;
 Electronics and Electrical Engineering