AN INVESTIGATION OF THE INTERFACE STATES OF THE GERMANIUM-SILICON ALLOYED HETEROJUNCTION.
PURDUE UNIV LAFAYETTE IND SCHOOL OF ELECTRICAL ENGINEERING
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The alloyed germanium-silicon heterojunction interface is studied to more conclusively determine if interface states exist due to dislocations, or if an impurity contamination exists at the interface. A profile of the mixing of he the silicon and germanium is determined for the alloyed heterojunction by employing an electron microprobe for a spectrochemical analysis. The mixing is shown to be diffusion controlled. In n-n type heterojunctions, a p-type layer is observed to form at the interface. Hall coefficient, conductivity and capacitance measurements are made on this p-layer using the p-n junctions to the bulk regions for isolation. From the electrical measurements and the electron-microprobe analysis, there is very strong evidence to show the interface states to be caused by dislocations. These measurements rule out the two sources of impurities as a cause of the interface states and show direct evidence of dislocations causing the interface states. It can therefore be concluded that the source of interface states in the alloyed germanium-silicon heterojunction is dislocations rather than impurities. Author
- Solid State Physics