Secondary defect profile related to low energy implanted boron measured upto 3.5 mu m depth into Si-substrates

Low energy implantation is one of the most promising options for ultra shal low junction formation in the next generation of silicon BiCMOS technology. Among the dopants that have to be implanted, boron is the most problematic because of its low stopping power (large penetration depth) and its tenden cy to undergo transient enhanced diffusion and clustering during thermal ac tivation. This paper reports an experimental study of secondary defect prof iles of low energy B implants in crystalline silicon. Shallow pen junctions were formed by low energy B implantation-10(15) cm(-2) at 3 keV-into a ref erence n-type crystalline silicon or pre-amorphized n-Si with germanium-10( 15) cm(-2) at 30 keV, 60 keV, and 150 keV. Rapid Thermal Annealing (RTA) fo r 15 s at 950 degrees C was then performed. Secondary defect profiles induc ed by this process are measured with isothermal transient capacitance in as sociation with Deep Level Transient Spectroscopy (DLTS). Relatively high co ncentrations of electrically active defects have been obtained up to 3.5 mu m into the crystalline silicon bulk. The relation of these defects with bo ron is discussed. The results of this study are in agreement with boron tra nsient enhanced diffusion in Si-substrate as has been reported by Collart u sing Secondary Ion Mass Spectrometry (SIMS) measurements.