Borosilicate glass was investigated as a dopant source for proximity rapid thermal diffusion. A borosilicate gel was spun onto a silicon wafer and the layer was rapid thermally processed to convert it to a borosilicate glass. Fourier transform infrared spectroscopy, spectroscopic ellipsometry, and sheet resistance measurements were used to understand and subsequently optimise the conversion of the gel to a borosilicate glass. The optimum conversion step, which avoided any boron loss from the borosilicate glass layer, was a curing step of 900ЊC for 45 s. Secondary ion mass spectrometry was used to measure the boron dopant profile of a silicon wafer that was doped with the borosilicate glass layer. The wafer had a surface dopant concentration of 4.7 ϫ 10 19 cm Ϫ3 and a junction depth of 65.5 nm. Junction diodes, which were fabricated using the glass layer as a dopant source, displayed excellent characteristics, with very low leakage currents and a near ideal forward slope.

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Thermal stress induced by rapid thermal oxidation (RTO) and rapid thermal doping (RTD) of 001 silicon wafers was analysed using micro-Raman spectroscopy and synchrotron x-ray topography. The RTO wafers exhibited elevated stress levels as the process time was increased. The maximum magnitude and topographical distribution of the strain was found to agree with theoretical predictions. A maximum compressive strain of 320 MPa was observed after 166 s of RTO. The introduction of boron into the silicon lattice via the RTD process enhanced the rate at which the stress in the wafer exceeded the yield stress. Stress relief was subsequently accomplished through the formation of slip and misfit dislocations. The thermally induced stress and dislocation density increased with the time spent at the process peak temperature.

Micro-Raman spectroscopy has been used for analysing the thermally induced stress distributions in silicon wafers after proximity rapid thermal diffusion (RTD). A compressive stress was found on the whole silicon wafer after 15 s RTD. After 165 s RTD the distribution of the stress across the wafer was found to be different: compressive at the edge and tensile at the middle. Thermal stress was relieved in the RTD wafers via slip dislocations. These slip dislocations were observed in the product wafers using optical microscopy. Slip lines propagated from the wafer edge to the wafer centre in 8 preferred positions of maximum induced stress. The thermally induced stress and the slip dislocation density increased with time spent at the RTD peak temperature.