Determination of bulk diffusion lengths for anglelapped semiconductor material via the scanning electron microscope: A theoretical analysis
Abstract
A standard procedure for the determination of the minority carrier diffusion length by means of a scanning electron microscope (SEM) consists in scanning across an anglelapped surface of a PN junction and measuring the resultant short circuit current I sub sc as a function of beam position. A detailed analysis of the I sub sc originating from this configuration is presented. It is found that, for a point source excitation, the I sub sc depends very simply on x, the variable distance between the surface and the junction edge. The expression for the I sub sc of a planar junction device is well known. If d, the constant distance between the plane of the surface of the semiconductor and the junction edge in the expression for the I of a planar junction is merely replaced by x, the variable distance of the corresponding anglelapped junction, an expression results which is correct to within a small fraction of a percent as long as the angle between the surfaces, 2 theta sub 1, is smaller than 10 deg.
 Publication:

Unknown
 Pub Date:
 May 1978
 Bibcode:
 1978dbdl.rept.....V
 Keywords:

 Diffusion Coefficient;
 Electron Microscopy;
 Minority Carriers;
 Semiconductor Junctions;
 Electric Current;
 Flat Surfaces;
 PN Junctions;
 Partial Differential Equations;
 SolidState Physics