论文部分内容阅读
本文报道对直拉硅单晶碳沾污机理的研究.用气相色谱法分析了石英与石墨反应生成物CO的蒸气压P_(co)以及拉晶条件下石英坩埚和石墨托之间反应的P_(co).在1512-1600K温度下测得不同载气Ar流速卞的P_(co),然后外推至零流速下的P_(co)~o数值,由此求得SiO_2-C反应产生的co平衡蒸气压值P_(co)~o. 在直拉硅单晶工艺过程中碳沾污的主要来源是石英坩埚与石墨托之间反应产生的CO.将上面结果与热力学数据比较,可以推出:SiO_2-C系在上面温度范围内的主要反应是:C+SiO_2→SiO+CO. 用钼片隔开石墨托与石英坩埚后,在拉晶过程中CO量减少,单晶头部<50％处碳含量在红外测量灵敏度以下.此外还研究了晶体中碳含量与层错密度的关系.
In this paper, the research on the mechanism of carbon black contamination of Czochralski silicon has been studied.The vapor pressure P_ (co) of CO and the reaction between quartz crucible and graphite support under the condition of crystal pulling have been analyzed by gas chromatography (co) .The P_ (co) of different carrier gas Ar flow rate was measured at the temperature of 1512-1600K and then extrapolated to the value of P_ (co) ~ o at zero flow rate, co balance vapor pressure P_ (co) ~ o. The main source of carbon contamination in the Czochralski silicon process is the CO produced by the reaction between the quartz crucible and the graphite holder. The above results can be compared with the thermodynamic data : The main reaction of SiO_2-C system in the above temperature range is: C + SiO_2 → SiO + CO. After separating graphite support and quartz crucible with molybdenum plate, the amount of CO decreases during the process of crystal pulling, the single crystal head <50 The carbon content below% is below the sensitivity of infrared measurement, and the relationship between the carbon content in the crystal and the layer-to-layer density has also been investigated.