アンモニア-過酸化水素溶液溶解/黒鉛炉原子吸光法によるヒ化ガリウムウェハー表面の極微量ケイ素の定量

概要

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A method for the determination of ultratrace Si on GaAs wafers has been investigated. A NH_4OH and H_2O_2 mixed solution was suitable for the dissolution of GaAs wafers. In the pretreatment procedure, a NH_4OH and H_2O_2 mixed solution and a polypropylenering was sandwiched between two GaAs wafers, so that it could dissolve the surface by shaking with a small volume of solution inside the polypropylene ring. The presence of Ga and As in the solution deteriorated the reproducibility of the Si measurement by graphite furnace AAS. The use of a NH_4Cl and HBr mixed solution as a matrix modifier recovered the reproducibility. The lower determination limit was 2 ng ml^<-1>, estimated as the concentration corresponding to 10-times the standard deviation of a blank solution. This value corresponded to a surface concentration of 14×10^<11> atoms cm^<-2> for 2-inch wafer, and 4×10^<11> atoms cm^<-2> for 3-inch wafer. According to the analytical results of various GaAs wafer samples, it was found that the concentration of Si on the surface of GaAs wafers was in the range of 10^<11>-10^<13> atoms cm<-2>.
社団法人日本分析化学会の論文
1997-10-05