Arsenic Doping of $n$-Type $\beta$-FeSi2 Films by Sputtering Method

概要

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High quality epitaxial $n$-type $\beta$-FeSi2 thin films prepared by alternate Fe/Si multilayer deposition were doped with arsenic as impurity by sputtering method. Doping sources were heavily arsenic-doped silicon chips placed on the surface of silicon target. The starting $\beta$-FeSi2 films before doping were typically $n$-type with a residual electron concentration of about $1.0 \times 10^{17}$ cm-3 and a mobility of about 260 cm2/V$\cdot$s. When arsenic concentration changed from $7.0 \times 10^{17}$ to $1.9 \times 10^{18}$ cm-3, net electron concentration increased from about $2.0 \times 10^{17}$ to $4.0 \times 10^{17}$ cm-3, and electron mobility decreased from 250 to 160 cm2/V$\cdot$s. Secondary ion mass spectroscopy (SIMS) measurements showed a homogeneous arsenic distribution in $\beta$-FeSi2 films and a small diffused region (about 50 nm) at the interface between $\beta$-FeSi2 and a Si substrate. Arsenic-doped $\beta$-FeSi2 films exhibited epitaxial growth in the (110)/(101) orientation and a continuous structure without cracks. However, other crystalline orientations together with pinholes appeared when the arsenic doping concentration increased.
Japan Society of Applied Physicsの論文
2005-02-10