DIFFUSION OF BORON A$ID PHOSPHORUS IN SIIJICON

jor professor This thesis presents some experimental results for producing control]ed PN and NPN diffused structures in silicon by varying the strength of the diffusion sources. Boron diffusions were carried out in. N2 atmosphere at l2oooc with Lo%, 2o%, 30 % and 40 % B2o3 ir silicic acid as sources. Phosphorus diffusions were carried out at 115ooq with a Pr0, source at temperatures of 22ooc, 300oc, 400oc and 5oooc and 02 as a carrier gas. For boron diffusions, the surface goncentration of the boron impurity atoms diffused into an N-type silicon wafer varied from 2. rB x Io17 to. l..45 x lo20 atoms,/cm3. " the composition of the sourse was changed. Similarly, for phosphorus dif fus j"ons, the surf ace concentratj-on of phosphorus impurity atoms diffused into a P-type silicon wafer varied from 1.8 x I0I8 to 9.5 x Lo2r atoms/crn3 the temperature of the source was changed. Post-diffusion, which consists of heating a silicon wafer previously diffused with impurity atoms, was-..----.-t_l Redacted for Privacy investigated to impuritlr atoms. structures were determine the Usi-ng these fabricated by redistributi.on of the results, NPN and FNP doubl-e dif fusions