
Principles of Analog Electronics
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8.3.3 Total Current
The total current density J in a semiconductor, which results from the motion of
charge carriers, can be the sum of four components depending on the type of
carriers, electrons, and/or holes, and the causes, drift or diffusion. Summarizing,
JJ J
with
JJ JnqEqD
dn x
nndriftn
diffusion
nn
=+ =µ+
JJ JpqEqD
dp x
ppdriftp
diffusion
=+ =µ−
8.3.4 Leakage Current
It is somewhat important to also dene the so called leakage current. In electron-
ics leakage current represents a parasitic and uncontrolled current, which ows
across regions of a material, not specically a semiconductor, where no