多次透射反射红外光谱法灵敏和准确地测量单晶硅中间隙氧和代位碳的含量

建立了室温下使用多次透射反射红外光谱法(MTR-IR)测量单晶硅中间隙氧和代位碳含量的新红外光谱吸收方法,在理论和实验上证明了MTR-IR优于常规使用的单次垂直透射红外(IR)吸收测量方法。与IR法相比较,MTR-IR法的优点为:(1)间隙氧在1 107 cm^-1处和代位碳在605 cm^-1处的吸收峰与MTR-IR法中红外光透过硅片的的次数N(6~12)成线性增加的正比例关系,因此单晶硅中间隙氧和代位碳含量的检测限至少比IR法低一个数量级;(2)MTR-IR法测量薄硅片如0.2 mm的厚度时产生的干涉条纹强度是单次垂直透射红外吸收法(IR)的1/23、是单次Brewster角透射红外吸收法的1/11;(3)单次垂直透射红外吸收法(IR)1次只测量样品上的1个点,MTR-IR法则在更长的样品上1次测量多个样品点,每次测量更具有代表性。理论计算和实验结果都证实了MTR-IR吸收法测量晶体硅中间隙氧和代位碳杂质含量的高灵敏度、可靠性和重复性。

Sensitive and Accurate Measurement of Interstitial Oxygen and Substitutional Carbon in Single Crystalline Silicon by Multiple Transmission-Reflection Infrared Spectroscopy (MTR-IR)

A new infrared spectroscopic measurement of interstitial oxygen and substitutional carbon in silicon wafers at room temperature by Multiple Transmission-Reflection Infrared Spectroscopy (MTR-IR) has been established. The superiority of MTR-IR to conventional IR has been analyzed first in principle by theoretical calculation and then verified by practical measurements of single crystalline silicon samples. The advantages of MTR-IR over conventional IR with a single normal incidence are: (1) The absorption bands of interstitial oxygen at 1 107 cm^-1 and substitutional carbon at 605 cm^-1 can be enhanced linearly with the simplified transmission times (N) between 6 and 12, which consequently extends the detection limit of oxygen and carbon at least one order of magnitude lower. (2) The strength of interference fringes can be decreased for a 0.2 mm thin silicon slice by 23 times as that from the single normal incidence and 11 times as that from the Brewster angle transmission respectively. (3) Not like the conventional IR method, only collecting data from one sampling point at each measurement, MTR-IR collects data from multiple sampling points in a longer sample for one measurement. Overall, both theoretical calculations and experimental results demonstrate the high sensitivity, reliability, and reproducibility of the MTR-IR spectroscopy on the measurement of impurities of interstitial oxygen and substitutional carbon of single crystalline silicon.