11:15 AM - 11:30 AM
[19a-Z29-9] Measurement of carbon concentration in silicon crystal
(XXII) Restart of the revision of the SEMI Standard
Keywords:silicon crystal, carbon concentration, infrared absorption
Carbon concentration in silicon crystal started from 1019/cm3. In the transistor and IC period, carbon affected the device performance. In the next LSI period, carbon reduced to about 1015/cm3 and did not affect the device performance. In the 21 th Century, Si power device became popular and it uses the radiation induced CO pair for the lifetime control. Therefore, the strict control and reduction is important and the lowest level of carbon concentration reduced to 1013/cm3 range. Carbon concentration measurement is done by the infrared absorption using the ASTM standard procedure first established in 1970. JEIDA established the advanced standard and the result was included in the ASTM revision in 1990. JEIDA was revised for the concentration reduction and the revision of ASTM started in 2014 for 1015/cm3 regime but was interrupted. We have developed the 2nd generation measurement procedure till 2018 down to 1013/cm3 and proposed the additional revision in 2019. The history of about 10 step activity is summarized in Tab. 1. Now the revision is restarted by the collaboration with the leading researchers and SEMI standard members over the world based on the preliminary draft of revision including 4 subjects solving the problem, reference material, baseline, instrument test, calibration, and polysilicon measurement. In addition, discussion on the following points started, to eliminate ambiguity and to make clear and easier procedures.