Photothermal radiometric investigation of implanted silicon: The influence of dose and thermal annealing (original) (raw)
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2003
Non-contact, non-intrusive photo-thermal radiometry (PTR) was used for monitoring the ion implantation of (ptype) industrial-grade silicon wafers. The silicon wafers were implanted with Boron in the dose range of Ixl0 ll -to-lxl0 16 ions/cm 2 at different implantation energies (10 keV-to-180 keV). The results indicated excellent sensitivity to the implantation doses and energies. This laser-based photothermal technique monitors harmonically photoexcited and recombining carriers and shows great potential advantages over existing methodologies for characterization of multiple semiconductor processes such as ion implantation and other device fabrication steps in the Si wafer processing industry.
Applied Physics Letters, 1997
Photothermal infrared radiometry was used for monitoring the ion implantation in Si wafers implanted with phosphorus to doses in the range of 5ϫ10 10 -1ϫ10 16 ions/cm 2 at different implantation energies. Quantitative results on the sensitivity of the carrier plasma-dominated radiometric signal to the implantation dose and energy are presented and compared to those obtained using a commercial implantation monitoring instrument.
Solid-State Electronics, 2005
Frequency-scanned and lock-in common-mode-rejection demodulation schemes were used with laser infrared photothermal radiometric (PTR) detection of B + , P + , and As + ion-implanted Si wafers, with or without surface-grown oxides. The implantation energy was 100 keV with doses in the range 1 · 10 11 -1 · 10 13 ions/cm 2 . The lock-in common-mode-rejection demodulation (CMRD) scheme exhibited superior signal resolution in all cases where the conventional frequency-scan signals were essentially overlapped. These were B + -implants in the dose range 1 · 10 12 -1 · 10 13 ions/cm 2 , and P + -implants in the 10 12 ions/cm 2 range.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2007
The dynamics of the nanosecond laser annealing of the implanted silicon by probing the implanted layer with infrared radiation (1.06 lm) in the conditions of the total internal reflection is investigated. The obtained experimental data are compared with the results of computer simulation of the studied processes. The data characterizing the contributions of intrinsic absorption of the probing beam and the absorption on free carriers generated in Si by laser radiation are obtained. The temperature dependence of the intrinsic absorption coefficient in Si during high-temperature heating is estimated.
Three-layer photocarrier radiometry model of ion-implanted silicon wafers
Journal of Applied Physics, 2004
A three-dimensional three-layer model is presented for the quantitative understanding of the infrared photocarrier radiometry ͑PCR͒ response of ion-implanted semiconductors, specifically Si. In addition to the implanted layer and intact substrate normally assumed in all existing two-layer theoretical models to describe the photothermal response of ion-implanted semiconductors, a surface layer is considered in this three-layer model to represent a thin, less severally damaged region close to the surface. The effects on the PCR signal of several structural, transport, and optical properties of ion-implanted silicon wafers affected significantly by the ion implantation process ͑minority carrier lifetime, diffusion coefficient, optical absorption coefficient, thickness of the implanted layer, and front surface recombination velocity͒ are discussed. The dependence of the PCR signal on the ion implantation dose is theoretically calculated and compared to experimental results. Good agreement between experimental data and theoretical calculations is obtained. Both theoretical and experimental results show the PCR dependence on dose can be separated into four regions with the transition across each region defined by the implantation-induced electrical and optical degrees of damage, respectively, as the electrical and optical damage occurs at different dose ranges. It is also shown that the PCR amplitude decreases monotonically with increasing implantation dose. This monotonic dependence provides the potential of the PCR technique for industrial applications in semiconductor metrology.
Ion implant dose dependence of photocarrier radiometry at multiple excitation wavelengths
Applied Physics Letters, 2004
The dependence of the photocarrier radiometric (PCR) signal on ion implant dose in Si is reported. The results show almost entirely monotonic behavior over a large range of industrially relevant fluences ͑1 ϫ 10 10 -1ϫ 10 16 cm −2 ͒ for 11 B + , 75 As + , 31 P + , and BF 2 + implanted in Si wafers at various energies. In addition, the use of excitation sources with a range of absorption coefficients is shown to be very useful in improving the sensitivity of the PCR amplitude to implant dose.
Activation of Silicon Implanted with Phosphorus Atoms by Infrared Semiconductor Laser Annealing
Japanese Journal of Applied Physics, 2007
We activated silicon implanted with phosphorus atoms by infrared semiconductor laser annealing with a diamond-like carbon (DLC) optical absorption layer. The silicon samples implanted with phosphorus atoms at 10 and 70 keV with concentrations of 5 Â 10 14 , 1 Â 10 15 , and 2 Â 10 15 cm À2 were coated with 200-nm-thick DLC films. The samples were annealed by irradiation with a 940 nm continuous wave laser at 70 kW/cm 2 with a beam diameter of 180 mm. The laser beam was scanned using a moving stage at 3-20 cm/s, which gave an effective dwell time of 0.9-6.0 ms. The amorphized surface regions were recrystallized by laser annealing longer than 1.2 ms. The in-depth profile of phosphorus concentration hardly changed within 5 nm for laser annealing for 2.6 ms. The sheet resistance markedly decreased to 106 and 46 /sq for the samples implanted with phosphorus atoms at 10 and 70 keV by laser annealing at a dwell time of 2.6 ms, respectively. Phosphorus atoms were effectively activated with a carrier density near the phosphorus concentration for implantation at 70 keV. A low carrier generation rate was observed for implantation at 2 Â 10 15 cm À2 and 10 keV. An intermediate SiO 2 layer effectively blocked carbon incorporation to a level below 10 17 cm À3 .
Athermal annealing of phosphorus-ion-implanted silicon
Applied Physics Letters, 2000
A 1 cm 2 area in phosphorus-implanted silicon samples is annealed by irradiation of a much smaller 0.002 cm 2 area with a single laser pulse. Resistivity of the annealed region is uniform and similar to that measured after thermal annealing. Electrically activated donors did not diffuse into the sample and only slightly towards the sample surface. The process is 100% reproducible. We present evidence that the annealing is not caused by heat.