Poly-silicon thin films by aluminium induced crystallisation of microcrystalline silicon

Al-induced crystallisation of microcrystalline Si thin films prepared by electron cyclotron resonance plasma-enhanced chemical vapour deposition (ECR–PECVD) on glass and SiO2 coated Si wafers has been studied. The starting structure was substrate/μc-Si/Al. Annealing this structure in the temperature range 370–520 °C, immediately following deposition of the Al layer, resulted in successful layer exchange and the formation of a substrate/Al+Si layer/poly-Si geometry. The top poly-Si layer exhibited grain sizes generally in the range ∼2–6 μm, although larger grains were also sparsely present. The films did not exhibit any appreciable degree of preferred orientation. The surface roughness was relatively high with a Ra value of ∼20 nm.