Characterization of Ion Implanted Silicon Annealed with a Graphite Radiation Source
A Varian IA-200 isothermal annealer has been used to anneal ion implantation damage and electrically activate dopants in As and B implanted silicon with minimal redistribution of the impurity. The anneal occurs in vacuum using infrared radiation from a resistively heated sheet of graphite. Good quality anneals of /sup 11/B implanted samples have been obtained with minimal boron diffusion. Arsenic implanted wafers have also be annealed with excellent results except for a substantial loss of As which occurs unless the wafer has an SiO/sub 2/ cap. The anneal quality of (100) wafers was independent of dose, however, the anneal quality of the (111) wafers improved with increasing As dose.
Scanned electron beam annealing of boron‐implanted diodes
Successful annealing of p+n diode arrays fabricated by ion implantation of 11B (50 keV, 1×1014 cm−2) into Si (100) has been performed using a broadly rastered, low‐resolution (0.25 in. diameter) electron beam. A complete 2 in. wafer could be uniformly annealed in ≃20 sec with electrical activation ≃75% and small dopant redistribution (∼450 A). Annealing resulted in p+n junctions characterized by low reverse current (?4 nA/cm2 at 5‐V reverse bias) and high carrier lifetime (≳80 μsec) over the entire 2 in. wafer. Based on the electrical characteristics of the diodes, we estimate that the electron beam anneal was able to successfully reorder the substrate and remove ion implantation damage near the p+n junction.
Characterisation of multiple-scan electron beam annealing method
Beam power per unit area and exposure time are the predominant factors in defining implant anneal conditions for the multiple scan electron beam annealing technique. A theoretical analysis is presented which agrees with experimental results. Carrier concentration profiles confirm that the implant becomes electrically active without diffusion.