In-situ monitoring of epitaxial film thickness by IEMI

In-situ measurement of epitaxial film thickness by infrared emission Michelson interferometer (IEMI) is presented. During in-situ experiments, epi wafers were heated inside an ultrahigh vacuum (UHV) single-wafer chemical vapor deposition (CVD) reactor or a furnace and the IR emission from the wafers was analyzed by the MI. In-situ thickness measurements have been made at temperatures ranging from 150 to 900 degrees C for a lightly doped epi layer (0.5 Omega -cm) on top of a heavily doped substrate (0.001-0.002 Omega -cm). The accuracy of in-situ measurements is 2% of the actual epi layer thickness, compared with 0.3% for ex-situ measurements. This technique can be applied to real-time in-situ measurements of epi film growth and to real-time control of epi film thickness.<
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