Surface morphologies of excimer-laser annealed BF2+ implanted Si diodes

✍ Scribed by A. Burtsev; H. Schut; L.K. Nanver; A. van Veen; J. Slabbekoorn; T.L.M. Scholtes

• Book ID: 104062023
• Publisher: Elsevier Science
• Year: 2004
• Tongue: English
• Weight: 186 KB
• Volume: 114-115
• Category: Article
• ISSN: 0921-5107
• DOI: 10.1016/j.mseb.2004.07.012

✦ Synopsis

Laser-induced surface roughness and damage formation in ultra-shallow n + -p and p + -n junctions, formed by low energy (5 keV) As + and BF 2 + implantations in Si, respectively, with a dose of 1 × 10 15 cm -2 have been investigated by atomic force microscopy (AFM) and Positron Annihilation Doppler Broadening (PADB) technique. The Si surface roughness is found to increase with laser energy density, and reaches a value of 3.5 nm after excimer-laser annealing (ELA) at 1100 mJ/cm 2 . However, anomalous behavior is witnessed for BF 2 + -implanted Si sample at 800 mJ/cm 2 , at which energy very high surface protrusions up to 9 nm high are observed. By PADB this behavior is correlated to extensive deep microcavity formation in the Si whereby the volatile F 2 fraction can accumulate and evaporate/out-diffuse, leading to Si surface roughening. The consequences for the diode characteristics and contact resistivity are examined.