SOME ANNEALING PROPERTIES OF LOW-ENERGY-ANTIMONY - IMPLANTED SILICON RESISTORS

Shallow-implanted antimony in silicon can be used in fabricating n-type silicon resistors with very low temperature coefficient of resistance (TCR), controllably and reproducibly. This paper reports a study of the sheet resistance of silicon resistors implanted with 121Sb at 10 keV, for various doses and annealing conditions. The methods used in fabricating samples and taking measurements were described in an earlier paper[1]. For high doses, ∼ 1015 Sb/cm2, we found that two-stage annealing[2]-preannealing at 550°C followed by annealing at 1000°C-improves the electrical conductivity. For low doses, ∼1012 Sb/cm2, the final annealing determines the conductivity. For medium doses, ∼1013-1014 Sb/cm2, the interplay of damage-annealing and activation of Sb in Si introduces complications, giving a crossover of shet resistance vs implant dose for various annealing temperatures. For doses around 3 × 1013 cm-2, the resistances are very insensitive to the details of annealing sequence and temperature; also the TCR is very low, about 50 ppm/°C. The effect of annealing conditions for various doses, resistivities and TCR values are discussed. © 1979.