Effects of dislocations on the noise of planar p-n junctions.

In this work edge dislocations are introduced by plastic deformation in silicon planar diodes. The effects of the dislocations on the electrical properties, especially noise are studied. The noise spectra for the diodes under forward bias conditions show that the shot noise is relatively unaffected by the dislocations, and the 1/f noise is only affected when the dislocations emerge at a surface near the junction. The most striking feature of the spectrum is the existence of a visible generation-recombination noise, which seems to be due to fluctuations in the occupation of trapping centers in the space charge region introduced by the dislocations.
In this work, silicon planar diodes have been deformed so as to introduce in them dislocations, in order to study the effects of the latter on the p-n junction characteristics. The main parameter which was investigated was the electrical noise caused by the dislocations. The shot noise was shown not to depend on the dislocations, and the 1/f noise was only affected when the dislocations emerged at the surface of the device near the junction. However, G-R noise was shown to be a function of the dislocation density. A theory was developed in which the G-R noise was attributed to an electron trapping process caused by the dislocations in the depletion region. The trapping model was shown to be in very good agreement with the experimental observations.
The main conclusion which can be drawn from this work is that dislocations in planar silicon diodes effect the noise spectra in two ways. The first way in which this occurs is that the 1/f noise is increased if the dislocations intersect a surface near the junction. The second way is that G-R noise is produced by fluctuations in the occupancy of traps caused by the dislocations. [ABSTRACT FROM AUTHOR]