Rapid thermal diffusion of aluminum in silicon and its interaction with phosphorus

Laser‐Doping through Anodic Aluminium Oxide Layers for Silicon Solar Cells

“…Although aluminium is incorporated in the silicon to approximately the same depth as the sample which was laser-doped through the AAO layer formed by aluminium anodisation in 0.5 M H 2 SO 4 and 0.5 M H 3 BO 3 (see Figure 1(b)), its concentration is higher in the doped region indicating increased aluminium incorporation in silicon in the presence of phosphorus. Nagel et al reported that solidstate diffusion of aluminium was enhanced in the presence of phosphorus due to field-assisted diffusion arising from aluminium diffusing as negatively charged ion and phosphorus diffusing as a positive ion-vacancy pair [23,26]. Furthermore, the aluminium profile in Figure 1(c) has a local minimum at 5 m. This is similar to the aluminium solid-state diffusion profile (in the presence of phosphorus) reported by Kuhlmann et al [23] that can be explained by the up-hill migration of aluminium ions towards the surface caused by the electric field of the phosphorus profile.…”

Crystal Growth of Silicon for Solar Cells

“…The measured The assessed diffusivity of Al in solid silicon was mainly based on the experimental data available in the literature [8,[97][98][99][100][101][102][103][104][105][106][107]. The measured The assessed diffusivity of Al in solid silicon was mainly based on the experimental data available in the literature [8,[97][98][99][100][101][102][103][104][105][106][107].…”

Modelling of Intrinsic Aluminum Diffusion for Future Power Devices

“…In recent publications, ion implantation [9,10] and electrical characterization methods like spreading resistance profiling have been used. Only few authors like [1,2,11] used more reliable characterization methods like secondary ion mass spectroscopy (SIMS). Especially for short diffusion times and low diffusion temperatures the diffusion of aluminum is characterized insufficiently.…”

“…Deep p n junctions, on the other hand, are often needed only to separate the space charge region around the p n junction from the layer of process induced defects. Modern concepts for the fabrication of power devices are therefore often based on short time processes at comparatively low temperatures [1,2] to avoid defect formation and contamination. Because of the traditional application of aluminum for deep p n junctions, most investigations covered temperatures above 1200 ¥ C. The results disagreed by up to a factor of 50 [3,4].…”