変形バイメタルモデルによる拡散不純物表面濃度の決定

概要

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A new method for measuring the surface concentration of the diffused impurity atoms is proposed. Because of the lattice distortion due to the distribution of the diffused impurity atoms, the substrate crystal is warped like bimetals. The equations to calculate the warpage angle of the substrate crystal are derived. The surface concentration of the diffused impurity of the substrate is decided so that the value calculated by the equations fits in the measured value of the warpage angle. The method was actually applied to {l00} GaAs substrates in which Cd atoms had been diffused at 1000℃ and 900℃ respectively. The calculated values of the warpage angle of the substrate assuming the complementary error function for the Cd distribution are in good agreement with the experimental values. The Cd-surface concentrations diffused at 1000℃ and 900℃ were decided as 1.3×10^<19> and 2×10^<18>cm^<-3>, respectively. For the reduction of the warpage angle when the diffused layer was removed, the theoretical values were also in good agreement with the experimental values. From these facts, therefore, the validity of the assumption of the complementary error function for the Cd-distribution were confirmed.
琉球大学工学部の論文