[14p-K306-1~3] 15.7 Crystal characterization, impurities and crystal defects

2:00 PM - 2:15 PM JST(5:00 AM - 5:15 AM UTC)

[14p-K306-3] Measurement of carbon concentration in silicon crystal/ 2-nd generation
(30) Solution of inner phonon band problem in infrared absorption (2) Liquid N T measurement

〇Naohisa Inoue¹, Shuichi Okuda¹, Shuichi Kawamata¹ (1.Osaka Metropolitan Univ. Radiation Research center)

Keywords:

silicon crystal,carbon concentration,infrared absorption

IR absorption is practical as well as scientific measurement technique of carbon concentration in Si. Low temperature measurement was dominant especially in early days and adopted in the ASTM Standard. Moreover in 2011, measurement at LT on the Avogadro crystal for 2x10¹⁴/cm³ was reported. It established as the base of science; accuracy of International System of Units.
We established RT measurement in 1987 and included in ASTM Standard for FTIR in 1990. In 2005 we measured 10¹⁴/cm³ at RT. In 2016 we identified the middle and inner phonon band problem at RT. In 2018, we reported the LT measurement of 10¹³/cm³. 5 samples with [C] lower than 1x10¹⁴/cm³ were measured. C concentration was obtained to be 10, 9, 6, 4, 1x10¹³/cm³, respectively. Instrumental detection limit was about 1x10¹³/cm³ and spectral detection limit was 2x10¹³/cm³. IR enabled 10¹⁴/cm³ measurement of poly-Si both at RT and LT, more sensitive at LT. Ratio between the absorption at RT and LT must be redetermined using FTIR.