Conventional Ion Implantation Research Articles

Effect of $\hbox{B}_{2}\hbox{H}_{6}$ Plasma Doping on the Shallow Trench Isolation in CMOS Image Sensor Device

We evaluate the electrical and optical properties of a complementary metal-oxide-semiconductor (CMOS) image sensor with shallow trench isolation (STI) sidewall doped by plasma-doping (PLAD) method using B2H6. PLAD can be used to fabricate an STI sidewall junction depth shallower than that fabricated using conventional beamline ion implantation. The use of B2H6 for the STI sidewall doping by PLAD facilitates the concurrent doping of numerous hydrogen atoms around the STI sidewall, thus improving the optical properties, such as temporal noise, crosstalk, and saturation, of the 1.75-μm pixel CMOS image sensor. Although the dark current performance was slightly degraded, it could be improved under more heavily doped conditions.

The effect of alloyed and/or implanted yttrium on the mechanism of the scale development on β-NiAl at 1100°C

This paper reports on the comparison of scale development on unmodified β-NiAl which contains volume and surface additions of yttrium. This reactive element was incorporated using conventional alloying (0.05 or 0.1 wt%) and ion implantation. The materials containing alloyed yttrium were also implanted with yttrium to study the combined influence of volume and surface additions. A two-stage oxidation approach was applied with the use of 18O2 as a tracer. The reaction temperature was 1100°C and the samples were oxidised for up to 64 h.The scale growth mechanism was followed with the aid of in-depth distributions of the oxygen isotopes across the scale using secondary ion mass spectrometry, the surface morphology of the scales was observed using scanning electron microscopy, while their phase composition was determined using photoluminescence spectroscopy.Similar stages of the scale evolution were observed for the growing scales. Initially the oxide layer consisted of transient oxides, and at its surface more or less developed blade-like surface grains were observed. Subsequently, phase-transformation-related cracks and round patches appeared, and finally ridges which successively covered the outer surface of the scale and constituted the outer layer of a duplex scale developed. The mechanism of scale growth was a mixed outward and inward, and the relative contribution of both mechanisms varied depending on the analysed scale region and on the oxidation stage. The cracks and patches were regions where the transient aluminas were preferentially transformed into α-Al2O3. The ridges formed in cracks essentially consisted of α-Al2O3. For the initial stages of oxidation, the transient aluminas and α-Al2O3 co-existed in the scales, while subsequently the latter prevailed and finally, became the only phase found in the oxide layers.The evolution rate of the scale was affected by alloyed and implanted yttrium additions: the former exhibited minor and content-dependent effect while the latter significantly retarded it.

Dark current reduction of Ge photodetector by GeO_2 surface passivation and gas-phase doping

We have investigated the dark current of a germanium (Ge) photodetector (PD) with a GeO₂ surface passivation layer and a gas-phase-doped n+/p junction. The gas-phase-doped PN diodes exhibited a dark current of approximately two orders of magnitude lower than that of the diodes formed by a conventional ion implantation process, indicating that gas-phase doping is suitable for low-damage PN junction formation. The bulk leakage (Jbulk) and surface leakage (Jsurf) components of the dark current were also investigated. We have found that GeO₂ surface passivation can effectively suppress the dark current of a Ge PD in conjunction with gas-phase doping, and we have obtained extremely low values of Jbulk of 0.032 mA/cm² and Jsurf of 0.27 μA/cm.

Analysis and optimization of propagation losses in LiNbO3 optical waveguides produced by swift heavy-ion irradiation

The propagation losses (PL) of lithium niobate optical planar waveguides fabricated by swift heavy-ion irradiation (SHI), an alternative to conventional ion implantation, have been investigated and optimized. For waveguide fabrication, congruently melting LiNbO3 substrates were irradiated with F ions at 20 MeV or 30 MeV and fluences in the range 1013–1014 cm−2. The influence of the temperature and time of post-irradiation annealing treatments has been systematically studied. Optimum propagation losses lower than 0.5 dB/cm have been obtained for both TE and TM modes, after a two-stage annealing treatment at 350 and 375∘C. Possible loss mechanisms are discussed.

The effect of alloyed and/or implanted yttrium on the mechanism of the scale development on β-NiAl at 1100°C

This paper reports on the comparison of scale development on unmodified β-NiAl which contains volume and surface additions of yttrium. This reactive element was incorporated using conventional alloying (0.05 or 0.1 wt%) and ion implantation. The materials containing alloyed yttrium were also implanted with yttrium to study the combined influence of volume and surface additions. A two-stage oxidation approach was applied with the use of 18O2 as a tracer. The reaction temperature was 1100°C and the samples were oxidised for up to 64 h.The scale growth mechanism was followed with the aid of in-depth distributions of the oxygen isotopes across the scale using secondary ion mass spectrometry, the surface morphology of the scales was observed using scanning electron microscopy, while their phase composition was determined using photoluminescence spectroscopy.Similar stages of the scale evolution were observed for the growing scales. Initially the oxide layer consisted of transient oxides, and at its surface more or less developed blade-like surface grains were observed. Subsequently, phase-transformation-related cracks and round patches appeared, and finally ridges which successively covered the outer surface of the scale and constituted the outer layer of a duplex scale developed. The mechanism of scale growth was a mixed outward and inward, and the relative contribution of both mechanisms varied depending on the analysed scale region and on the oxidation stage. The cracks and patches were regions where the transient aluminas were preferentially transformed into α-Al2O3. The ridges formed in cracks essentially consisted of α-Al2O3. For the initial stages of oxidation, the transient aluminas and α-Al2O3 co-existed in the scales, while subsequently the latter prevailed and finally, became the only phase found in the oxide layers.The evolution rate of the scale was affected by alloyed and implanted yttrium additions: the former exhibited minor and content-dependent effect while the latter significantly retarded it.

Localized Ion Implantation Through Micro/Nanostencil Masks

A method is presented that allows the definition of micrometer- and submicrometer-sized implanted structures in silicon without using photoresist patterning. The process is based on the use of stencils as masks in a conventional ion implanter, and is tested for both phosphorus and arsenic ions. Electrical characterization confirms the activation of the impurities in the implanted zones whereas topological characterization shows minimum dimensions of 110 nm with an increase in dimensions compared to stencil apertures that is dominated by backscattering of the ions during implantation.

Ion implantation techniques for non-electronic applications

Ion implantation techniques have been used to improve surface properties for over more than four decades. Metallurgical application of ion beam techniques was first reported in the 70s by Harwell laboratory (UK), and by the Naval Research Laboratory (USA), mainly focused to nitrogen implantation of steels. From those first results to today ion implantation techniques have been introduced in many different applications for industrial sectors such as the aeronautical and biomedical. This paper presents some of the most important actual applications of ion implantation techniques. Different strategies of conventional Ion Implantation (II), Low energy-High Temperature Ion Implantation (LEHT), and Plasma Immersion Ion Implantation (PIII) are studied and compared in terms of modified surface properties and industrial application niches. Furthermore, the reported results show how these different treatments have a big potential for research in smart and nano-functional surfaces in applications including biomaterials and many other specific developments.

Ion induced bending (IIB) phenomenon for 3-D structure fabrication

We propose a thin-film bending technique based on the ion-induced bending (IIB) phenomenon, which enables the fabrication of three-dimensional structural devices and arrays, such as micro-electro mechanical system (MEMS) devices. We investigated the IIB phenomenon with various film materials and various ion species. It was found that the distribution of vacancy occurs under ion-irradiation was the important parameter affecting the degree of bending, irrespective of film material and ion-species. Therefore, it was found that the bending angle could be controlled by the distribution of vacancy. Using this technique, a micron-sized region of a standing thin-film array could be produced using conventional ion-implantation equipment used in semiconductor manufacturing.

Multi-Gate Fin Field-Effect Transistors Junctions Optimization by Conventional Ion Implantation for (Sub-)22 nm Technology Nodes Circuit Applications

In this work we explore several doping schemes for aggressively scaled multi-gate field-effect transistor devices with the conduction channels wrapped around silicon fins (FinFETs) (HFin∼37 nm, WFin≥10 nm, Lg≥30 nm), using conventional ion implantation (I/I), and suitable for both logic and dense circuit applications. We demonstrate that low-energy and: 1) low-tilt, double-sided extension(-less) I/I, or 2) high-tilt, single-sided extension I/I schemes can enable pitch scaling without resist shadowing effects, with no penalty in device performance and yielding higher six transistors-static random access memory (6T-SRAM) static noise margin (SNM) values. Key advantages of the extension-less approach are: reduced cost and cycle time with 2 less critical I/I photos, enabling better quality, defect-free growth of Si-epitaxial raised source/drain (SEG), and up to 20× lower IOFF. It, however, requires a tight spacer critical dimension (CD) control, a less critical parameter for the single-sided I/I scheme, which also allows wider overlay margins.

Advantage of Plasma Doping for Source/Drain Extension in Bulk Fin Field Effect Transistor

The impact of plasma doping (PD) on the formation of source/drain extension (SDE) is demonstrated for a p-type bulk fin field effect transistor (FinFET). The impurity distribution in a narrow fin (15 nm) was analyzed with atom probe tomography (APT) and secondary ion mass spectroscopy (SIMS). The lateral distribution of boron in the Si fin by the PD is similar to the case with conventional beam-line ion implantation (BL). However, the vertical distribution of boron by the PD is much steeper than that by the conventional BL. TCAD simulations show that the driving current of the FinFET fabricated by the PD is 34% higher than that of the FinFET fabricated by the BL under the same off-leakage current. Therefore, the PD is a key technology for fabricating the SDE of narrow bulk-FinFETs in the future.

Multi-Gate Fin Field-Effect Transistors Junctions Optimization by Conventional Ion Implantation for (Sub-)22 nm Technology Nodes Circuit Applications

Multi-Gate Fin Field-Effect Transistors Junctions Optimization by Conventional Ion Implantation for (Sub-)22 nm Technology Nodes Circuit Applications

High-Performance $\hbox{GeO}_{2}/\hbox{Ge}$ nMOSFETs With Source/Drain Junctions Formed by Gas-Phase Doping

We reveal that the MOVPE-based gas-phase doping can yield lower arsenic diffusion constant and lower leakage current n <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> /p junctions in Ge compared with conventional ion-implantation doping. Thus, the gas-phase doping is quite effective for realizing high-performance Ge n-channel MOSFETs. By using gas-phase doping for source/drain junction formation, the (100) GeO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /Ge nMOSFETs have achieved high electron mobility of 1020 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /V·s while maintaining low junction leakage current and high I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</sub> /I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</sub> ratio of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sup> . Furthermore, the (110) GeO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /Ge nMOSFETs have also shown high electron mobility and high I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</sub> /I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</sub> ratio.

EELS and STEM analysis of metal nitride/substrate interfaces

Nitride based protective coatings produced by physical vapour deposition offer a promising means to extend the oxidation and wear performance of γ-TiAl. Metal ion pre-etching of the substrate surface has been shown to significantly enhance the adhesion between the coating and substrate. In this study we have applied spectroscopic imaging and advanced STEM analysis to study such interfaces. For a conventional Cr cathodic arc discharge Cr ion implantation of ~6nm into the substrate was observed. For an etch using high power impulse magnetron sputtering the metal ion implantation depth was reduced to ~2-3nm. In both cases a corresponding depletion zone of Ti and Al was observed. In addition, nitrogen diffusion into the substrate during coating deposition was also revealed to a similar depth respectively.

Hybrid plasma surface modification and ion implantation of biopolymers

In conventional plasma immersion ion implantation (PIII), the sample is immersed in an externally sustained plasma. Negative high voltage pulses are applied to the sample stage to establish an ion sheath around the sample in order to implant ions into the materials. The polymer surface properties can be simply varied by changing the duty cycle between pulse on (ion implantation) and pulse off (plasma exposure) periods during PIII treatment. A high ratio between ion implantation and plasma exposure time can be achieved by increasing the pulsing frequency and elongating the pulse duration. The bioactivity of two polymers surface, polycarbonate and polytetrafluoroethylene (PTFE) is investigated where PIII ion implantation is the dominating effect. Two different polymers are treated by two different ions, e.g., argon and oxygen in two different laboratories demonstrating that the concept of long pulse, high frequency PIII can be converted to different polymers and different experimental systems. It showed that the implanted polycarbonate area did not turn dark blue after applying tetramethyl benzidine (TMB) showing that the horseradish peroxidase HRP was either lost or inactivated. However, after long pulse (200 µs) and high frequency (500 Hz) Oxygen PIII treatment, PTFE surfaces enhanced bacteria and cell attachment.

Patterned p-Doping of InAs Nanowires by Gas-Phase Surface Diffusion of Zn

Gas phase p-doping of InAs nanowires with Zn atoms is demonstrated as an effective route for enabling postgrowth dopant profiling of nanostructures. The versatility of the approach is demonstrated by the fabrication of high-performance gated diodes and p-MOSFETs. High Zn concentrations with electrically active content of approximately 1 x 10(19) cm(-3) are achieved which is essential for compensating the electron-rich surface layers of InAs to enable heavily p-doped structures. This work could have important practical implications for the fabrication of planar and nonplanar devices based on InAs and other III-V nanostructures which are not compatible with conventional ion implantation processes that often cause severe lattice damage with local stoichiometry imbalance.

Exploring doping options and variability of trigate transistors using atomistic process and device simulations

This work explores several options for the channel-stop implant and source/drain doping for bulk trigate transistors using three-dimensional atomistic simulation. Considering tight silicon fin spacing and difficulty of using conventional ion implantation for the source/drain doping, the authors model both the implantation and plasma doping options. Considering the size of silicon fin and a handful of dopant atoms at play, the kinetic Monte Carlo approach offers a natural way of investigating atomistic effects and device variability. Atomistic device simulation provides an insight into the impact of different doping options on performance and variability of the trigate transistors. The provided insight is instrumental in selecting the best doping options and optimizing the tradeoff between performance and variability.

Increased Biocompatibility and Bioactivity after Energetic PVD Surface Treatments

Ion implantation, a common technology in semiconductor processing, has been applied to biomaterials since the 1960s. Using energetic ion bombardment, a general term which includes conventional ion implantation plasma immersion ion implantation (PIII) and ion beam assisted thin film deposition, functionalization of surfaces is possible. By varying and adjusting the process parameters, several surface properties can be attuned simultaneously. Extensive research details improvements in the biocompatibility, mainly by reducing corrosion rates and increasing wear resistance after surface modification. Recently, enhanced bioactivity strongly correlated with the surface topography and less with the surface chemistry has been reported, with an increased roughness on the nanometer scale induced by self-organisation processes during ion bombardment leading to faster cellular adhesion processes.

Selective cell adhesion on an ion implanted poly(bisphenol A carbonate) film

Conventional ion implantation has been shown to modify the surface properties of polymers such as their hardness, conductivity, and biocompatibility. In this study, poly(bisphenol A carbonate) (PC) films were implanted by Ar + ions with an energy level of 100 keV in order to improve their biocompatibility. The results of the surface analyses revealed an increasing intensity of the functional groups on the ion implanted PC surfaces such as OH, C O, and C O after implantation, which contributed to an improvement of their hydrophilicity. The in vitro cell culture test revealed that the HaCaT cells were selectively adhered to the ion implanted regions of the PC.

Improved bio-tribology of biomedical alloys by ion implantation techniques

Surface modification of biomaterials by conventional ion implantation (II) and plasma immersion ion implantation (PI3) are innovative methods to improve the biocompatibility of these advanced materials. This paper describes the biocompatibility improvements of Ti6Al4V and Co28Cr6Mo implanted with N and O in a conventional implantation and a plasma immersion ion implantation processes. Tribo-corrosion friction and wear tests were performed in a realistic environment – in Hank’s solution – to investigate the introduced modifications. The wear performance was only slightly improved due to a thin layer thickness, whereas, in contrast, the corrosion rate was significantly reduced.

SIMS/ARXPS—A New Technique of Retained Dopant Dose and Profile Measurement of Ultralow-Energy Doping Processes

A newly developed surface analysis technique, which combines secondary ion mass spectrometry with angle-resolved X-ray photoelectron spectroscopy, was used to achieve more accurate results of the retained impurity doses and profiles for ultralow-energy implants, including conventional beamline implant and plasma immersion ion implantation (PIII). Using this method, it has been found that the B <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> (diborane) PIII demonstrates thicker native oxide and much more B dose loss during rapid thermal processing and surface-cleaning treatments than conventional beamline ion implantation, due to the higher surface B concentration. In order to match the electrical parameters of the device, PIII must consider higher nominal dose to compensate the B loss.