Investigation of Excimer Laser Annealing of Si using Photoluminescence at Room Temperature

Abstract

Laser annealing can be used for applications that require confinement of heat on the top surface in order to preserve the integrity of buried structures. To confine heat near the silicon surface, the most appropriate tool is UV laser. Here, two excimer lasers with different characteristics were used to anneal boron in silicon. The first one has pulse duration of about 180ns and the second one of about 20ns in scanning mode. Regarding the crystal damage characterization, we report that room temperature photoluminescence (RT-PL) is a powerful and non-destructive technique to monitor crystal damage evolution. In order to investigate the effect of a surface oxide on laser annealing, samples with different (1, 20 and 150 nm-thick) surface oxide layers have been annealed. From RT-PL data, the crystal quality is found to improve with increasing laser power density. However the presence of the oxide layer leads to sudden degradation of the PL response for laser energy densities exceeding the melting threshold of Si.

Activation of shallow B and BF<inf>2</inf> implants in Si using Excimer laser annealing

“…At annealing energy density below melting threshold, the BF 2 -implanted wafer exhibits lower PL intensity, probably because of heavier implantation-induced damages. Around melting threshold, both B and BF 2 cases display a sharp increase of PL signals, and for energy densities beyond 1,95J/cm², they stabilize at similar level, indicating then, a similar damage-curing effect [5]. Fig.…”

Room Temperature Photoluminescence and Ultraviolet Raman Characterization of Boron Implanted Silicon under Various Laser Annealing Conditions

“…5 Room temperature PL (RTPL) studies on ultrashallow and shallow implanted Si with high doses ( 1.0 × 10 15 cm −2 ), have been reported with other characterization results with Raman spectroscopy, sheet resistance measurements and secondary ion mass spectroscopy (SIMS) data. [6][7][8][9][10] For ultra-shallow and shallow implanted junction characterization, UV Raman spectroscopy with shallow probing depths (<50 nm) is very effective. 8,[11][12][13] In complementary metal-oxide-semiconductor (CMOS) image sensor fabrication processing, low-energy (up to few keV) and low dose (up to 5.0 × 10 14 cm −2 ) B + -implantation and laser annealing are frequently used.…”

The Impacts of Back-Surface Passivation Using Shallow Ion Implantation and Pulsed Laser Thermal Annealing on Back-Illuminated CMOS Image Sensors Performances: Physical and Electrical Characterizations

“…Furthermore, the RT-PL results exploiting could allow a one to one correlation between PL intensities and blue sensitivity results. Indeed, photoluminescence mapping has recently been shown to be an industrial inline way to access easily the crystalline quality upon LTA processing [5,6]. However, in this work it is also used to help to understand pixels sensitivity especially in terms of short wavelength as it will be shown on devices performed in the same conditions.…”