| The application of rapid thermal processing, RTP, is critical to the silicon processing community. The creation of high dose (>10 20/cm3), low resistivity (<600 ohm/square), shallow junctions (<25 nm), requires RTP techniques that restrict diffusion and activate a significant fraction of the implanted dopant species. A new technology, electromagnetic induction heating (EMIH), achieves rapid heating by directly coupling electromagnetic radiation into the silicon wafer. Heating rates of 125°C/sec to temperatures in excess of 1050°C were consistently achieved for 75 mm and 100 mm diameter wafers at input powers of 1000 and 1300 watts respectively. These ramp rates are suitable for ultra shallow junction formation, and junctions shallower than 25 nm with sheet resistances lower than 600 ohms/square have been achieved. This work describes the application of electromagnetic heating, details the theory behind EMIH using Maxwell's equations, discusses efficient field-wafer coupling, and analyzes the material dependence on heating. The experimental systems constructed to implement this heating technique along with heating results as a function of power are also provided.;EMIH was used to create ultra-shallow junctions and to study the transport of boron in silicon. The ultra-shallow junctions created satisfy the 90 nm CMOS technology node, as defined by SEMATECH, and are comparable to those achieved with comparable lamp-based anneal systems. The transport of boron was directly linked to the concentration of boron interstitials, BI, and silicon vacancies, VSi. Si interstitials, SiI, and oxygen atoms were found to annihilate VSi, limiting activation and increasing transport. The oxidation of the silicon by ambient oxygen also consumed boron dose, increasing sheet resistance, and led to an increased out-diffusion of F from the Si. Fluorine atoms were found to bind Si I and BI in Si-F and B-F bonded complexes. This limited boron transport and prevented the SiI from annihilating VSi, improving the statistical likelihood of boron activation. Finally, EMIH at 2.45 GHz has an optimal anneal temperature that is 100°C lower than that of comparable lamp-based anneal systems. This either indicates the existence of a microwave induced ponderomotive force or illustrates the role of optical illumination in the diffusion and activation of boron in silicon. |
