Frank Torregrosa

Bio: Frank Torregrosa is an academic researcher. The author has contributed to research in topics: Plasma-immersion ion implantation & Ion implantation. The author has an hindex of 5, co-authored 30 publications receiving 102 citations.

Realization of ultra shallow junctions by PIII: application to solar cells

Abstract: The efficiency of plasma immersion ion implantation (PIII) is no more to prove for the realization of ultra shallow junctions (USJ) in semiconductor applications. Interest for the fabrication of submicrometer CMOS devices is well known, but the ability of PIII to implant quickly high doses at very low energy and low price makes it a good candidate for the fabrication of solar cells. In this paper, we present results obtained by a semi-industrial prototype of PIII (PULSION®) designed by the French company IBS. First, metallic contamination, homogeneity, reproducibility, and SIMS profiles of ultra shallow junctions made by PULSION® BF 3 implantation on 200-mm silicon wafers are presented. Results are compared with BF 2 + implantations made on an AXCELIS NV-8200P beam line implanter and demonstrate the compatibility with semiconductor requirements. Then, results on solar cells with BF 3 shallow junctions made by PIII are presented. The simulated and measured internal quality factor (IQE) with an improved behavior in blue wavelengths demonstrates the interest of PIII for this applications field.

Ultra shallow P+/N junctions using plasma immersion ion implantation and laser annealing for sub 0.1 μm CMOS devices

Abstract: Classical beam line ion implantation is limited to low energies and cannot achieve P+/N junctions requested for Compared to conventional beam line ion implantation limited to a minimum energy implantation of 200 eV, plasma immersion ion implantation (PIII) is an emerging technique to get ultimate shallow profiles (as-implanted) due to no lower limitation of energy and high dose rate. On the another hand, laser thermal processing (LTP) allows to obtain very shallow junction with no TED, abrupt profile and activated depth control. In this paper, we show the implementation of the BF3 PIII associated with the LTP. Ions from BF 3 + plasma have been implanted in 200 mm n-type silicon wafers with energies from 100 eV to 1 keV and doses from 3E14 to 5E15 at/cm2 using PULSION® (IBS PIII prototype). Then, wafers have been annealed using SOPRA VEL 15 XeCl excimer lasers (l = 308 nm, 200 ns, 15 J/pulse) with energy density from 1 to 2.5 J/cm2 and 1, 3 or 10 shots. The samples have been characterized at CEA LETI by secondary ion mass spectrometry (SIMS) combined with four points probe sheet resistance measurements.

3C-SiС Hetero-Epitaxially Grown on Silicon Compliance Substrates and New 3C-SiС Substrates for Sustainable Wide-Band-Gap Power Devices (CHALLENGE)

Abstract: The cubic polytype of SiC (3C-SiC) is the only one that can be grown on silicon substrate with the thickness required for targeted applications. Possibility to grow such layers has remained for a long period a real advantage in terms of scalability. Even the relatively narrow band-gap of 3C-SiC (2.3eV), which is often regarded as detrimental in comparison with other polytypes, can in fact be an advantage. However, the crystalline quality of 3C-SiC on silicon has to be improved in order to benefit from the intrinsic 3C-SiC properties. In this project new approaches for the reduction of defects will be used and new compliance substrates that can help to reduce the stress and the defect density at the same time will be explored. Numerical simulations will be applied to optimize growth conditions and reduce stress in the material. The structure of the final devices will be simulated using the appropriated numerical tools where new numerical model will be introduced to take into account the properties of the new material. Thanks to these simulations tools and the new material with low defect density, several devices that can work at high power and with low power consumption will be realized within the project.

Influence of Heating and Cooling Rates of Post-Implantation Annealing Process on Al-Implanted 4H-SiC Epitaxial Samples

Abstract: We report on topographical, structural and electrical measurements of aluminum-implanted and annealed 4H-SiC epitaxial samples. The influence of heating-up and cooling-down temperature rates on the SiC surface roughness, the crystal volume reordering and the dopant electrical activation was particularly studied. A higher heating-rate was found to preserve the rms roughness for annealing temperatures lower than 1700°C, and to improve the sheet resistance whatever the annealing temperature due to a better dopant activation (except for 1600°C process, which induced a dark zone in the sample volume). A complete activation was calculated for an annealing at 1700°C during 30 minutes, with a ramp-up at 20°C/s. Rising the cooling-down rate appeared to increase the sheet resistance, probably due to a higher concentration of point defects in the implanted layer.

4H-SiC P + N UV Photodiodes : A Comparison between Beam and Plasma Doping Processes

Abstract: This paper presents a study of 4H-SiC UV photodetectors based on p+n thin junctions. Two kinds of p+ layers have been implemented, aiming at studying the influence of the junction elaborated by the ion implantation process (and the subsequent annealing) on the device characteristics. Aluminum and Boron dopants have been introduced by beam line and by plasma ion implantation, respectively. Dark currents are lower with Al-implanted diodes (2 pA/cm2 @ - 5 V). Accordingly to simulation results concerning the influence of the junction thickness and doping, plasma B-implanted diodes give rise to the best sensitivity values (1.5x10-1 A/W @ 330 nm).

Plasma-based ion implantation and deposition: a review of physics, technology, and applications

Abstract: After pioneering work in the 1980s, plasma-based ion implantation (PBII) and plasma-based ion implantation and deposition (PBIID) can now be considered mature technologies for surface modification and thin film deposition. This review starts by looking at the historical development and recalling the basic ideas of PBII. Advantages and disadvantages are compared to conventional ion beam implantation and physical vapor deposition for PBII and PBIID, respectively, followed by a summary of the physics of sheath dynamics, plasma and pulse specifications, plasma diagnostics, and process modeling. The review moves on to technology considerations for plasma sources and process reactors. PBII surface modification and PBIID coatings are applied in a wide range of situations. They include the by-now traditional tribological applications of reducing wear and corrosion through the formation of hard, tough, smooth, low-friction, and chemically inert phases and coatings, e.g., for engine components. PBII has become viable for the formation of shallow junctions and other applications in microelectronics. More recently, the rapidly growing field of biomaterial synthesis makes use of PBII and PBIID to alter surfaces of or produce coatings on surgical implants and other biomedical devices. With limitations, also nonconducting materials such as plastic sheets can be treated. The major interest in PBII processing originates from its flexibility in ion energy (from a few electron volts up to about 100 keV), and the capability to efficiently treat, or deposit on, large areas, and (within limits) to process nonflat, three-dimensional workpieces, including forming and modifying metastable phases and nanostructures.

Trends in semiconductor defect engineering at the nanoscale

Abstract: Defect engineering involves manipulating the type, concentration, spatial distribution, or mobility of defects within a crystalline solid. Defect engineering in semiconductors has become much more sophisticated in recent years, driven by the need to control material properties at small length scales. The present article describes recent trends in defect engineering across several nano-oriented applications, beginning with Si-based integrated circuits and extending into non-Si microelectronics and especially into oxide semiconductors for sensors and photocatalysis. Special focus fixes upon physical mechanisms that have been little exploited up to now, but show significant promise as new means for controlling defect behavior, including low-energy ion bombardment, surface chemistry, and photostimulation. Systems-based methods for parameter estimation offer considerable promise for helping to understand the complex diffusion and reaction networks that characterize defect behavior in most prospective applications.

Defect engineering in metal oxides via surfaces

Abstract: The present invention provides methods for controlling defects in materials, including point defects, such as interstitials and vacancies, and extended defects, including dislocations and clusters. Defect control provided by the present invention allows for fabrication and processing of materials and/or structures having a selected abundance, spatial distribution and/or concentration depth profile of one or more types of defects in a material, such as vacancies and/or interstitials in a crystalline material. Methods of the invention are useful for processing materials by controlling defects to access beneficial physical, optical, chemical and/or electronic properties.