Effect of Silicon Nitride Cap on the Activation of Implanted Silicon in Gallium Arsenide

概要

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The effect of silicon nitride (SiNx) anneal cap on the activation efficiency ($\eta$) of the implanted Si in gallium arsenide (GaAs) was investigated. SiNx films of various N/Si ratios were prepared, changing the NH3/SiH4 source gas ratio in plasma enhanced chemical vapor deposition (PECVD). As a result, $\eta$ of the n-layer was found to become the maximum when the SiNx had a slightly N-rich composition. Device simulation clarified that the maximum $\eta$, which was obtained with an annealing temperature of 805°C, was 75%. Stress measurements at high temperatures demonstrated that the compressive stress increment at 805°C hardly improved $\eta$. On the other hand, the amount of the Ga out-diffusion measured by the total reflection X-ray fluorescence (TXRF) was found to correspond to the trend of $\eta$. In the activation with the SiNx caps in this study, the Ga out-diffusion was more dominant than the stress.
2003-08-15