Effect Of Fluorine Implantation Research Articles

Effect of fluorine implantation on recovery characteristics of p-channel MOSFET after negative bias temperature instability stress

In this paper, the effect of fluorine implantation on the recovery characteristics of p-channel MOSFETs (PMOSFETs) after negative bias temperature instability (NBTI) stress was investigated. PMOSFETs using fluorine ion implantation (F-I/I) performed better than those without F-I/I after NBTI stress; it is thought that F-I/I can suppress the generation of permanent damage during NBTI stress. The relationship of ΔVth and ΔSS during NBTI stress and recovery showed how much permanent damage occurred. In addition, we confirmed with a 1/f noise measurement that the device with F-I/I was immune to NBTI stress in spite of a pre-existing bulk trap caused by implantation damage. Moreover, the device with F-I/I had greater activation energy than the device without F-I/I. As indicated by the results, fluorine implantation can decrease the generation of permanent damage under NBTI stress because of the stable Si–F bond.

Effects of Fluorine Implantation on 1/<I>f</I> Noise, Hot Carrier and NBTI Reliability of MOSFETs

Effects of Fluorine Implantation on 1/<I>f</I> Noise, Hot Carrier and NBTI Reliability of MOSFETs

Advantages of LDD-only implanted fluorine with submicron CMOS technologies

The effect of fluorine implantation on the properties of shallow n/sup +//p junctions has been investigated. The novel approach of this work lies in the introduction of fluorine only in the LDD regions of the device and not in the active region underneath the gate. Gated diodes were used as test vehicles to study the effect of the fluorine incorporation. Gated diodes are ideal for measurements of this nature since they are sensitive to changes in the interfacial properties near the gate to diffusion overlap region. Results from electrical device characterization indicate a reduction in gated diode leakage and mid-gap interface state density as the F-implanted dose is increased without causing any significant change in the flat-band voltages. Results also showed that samples with F incorporation tended to be more robust to electrical stress than those without F. Materials analysis indicated reduced junction depths for samples with F introduced in the LDD regions indicating suppression of phosphorus dopant diffusion.

Current transport in fluorine implanted GaAs

Effects of fluorine implantation in GaAs have been investigated by electrical characterization. Ion implantation at 100 keV energy was conducted with doses of 1011 and 1012/cm2. The effect of fluorine implantation on current-voltage (I-V) characteristics of Schottky diodes was significant. Carrier compensation was observed after implantation by the improved I-V characteristics. The lower dose implanted samples showed thermionic emission dominated characteristics in the measurement temperature range of 300 to 100K. The starting wafer and the low dose implanted samples after rapid thermal annealing (RTA) showed similar I-V properties with excess current in the lower temperature range dominated by recombination. The higher dose implanted samples showed increased excess current in the whole temperature range which may result from the severe damage-induced surface recombination. These samples after RTA treatment did not recover from implantation damage as in the low dose implantation case. However, very good I-V characteristics were seen in the higher dose implanted samples after RTA. The influence of the higher dose ion implantation was to produce more thermal stability. The results show the potential application of fluorine implantation in GaAs device fabrication.

Simultaneous elimination of electrically active defects in Si/SiO 2 structures by implanted fluorine

The effect of fluorine implantation on oxide and interface trapping centres in Si/SiO 2 structures has been investigated using charge injection techniques. Significant reduction of the density of various defects has been observed for ultra-dry and wet oxides after F-implantation. The elimination of the traps takes place in a correlated manner despite the different nature of the centres. The catalytic action of fluorine via strain relaxation or release of defect passivating species is proposed to be the cause of the observed effect.

Effects of fluorine implantation into a-C:H thin films

Fluorine implantation into r.f. glow discharge hydrogenated amorphous carbon (a-C:H) has been performed and the properties of the implanted a-C:H films as functions of the implanted fluorine concentration C F have been studied using optical absorption, electrical and electron spin resonance (ESR) measurements. When C F is below 10 19 cm −3, the optical gap E opt does not change significantly with C F. However, for higher C F values E opt decreases rapidly with increasing C F from 1.53 eV at C F = 1 × 10 19 cm −3 to about 1 eV at C F = 1 × 10 21 cm −3. It is found that effective doping of the a-C:H films has been achieved when C F exceeds about 10 20 cm −3. The conductivity activation energy E a drops significantly from 1.28 eV for the unimplanted and unannealed sample to 0.2 eV for the implanted and annealed sample with C F = 3 × 10 21 cm −3. An increase of more than 10 orders of magnitude in σ RT has been observed between samples with sufficiently high C F values and unimplanted samples. In addition to a large main resonance due to carbon dangling bonds of g value g 1 = 2.0027 ± 0.0002, hyperfine splitting (HFS) has been induced by the implanted F atoms in the ESR spectra measured in the dark at the X band position at room temperature. However, these HFS signals exhibit a peculiar C F dependence and do not show up in some intermediate C F value range. For C F higher than about 10 20 cm −3 the large main resonance is also found to be composed of one big lorentzian component and one small gaussian component. While all the HFS signals annealed out at 200°C, the small gaussian component persisted even after annealing at 250°C.

Effects of Fluorine Implantation into Hydrogenated Amorphous Silicon

ABSTRACTMultiple-energy implantation of fluorine into rf glow discharge deposited hydrogenated amorphous silicon (a-Si:H) thin films has been performed. It is found that the optical gap decreases with the implanted fluorine concentration CF from 1.56 eV for the unimplanted sample to 1.40 eV for the sample with CF of 3×1021 cm−3. Results of the Staebler-Wronski experiment show that the ratio between the electrical conductivity before and after illumination, as well as the ratio between the photo- and dark conductivity, decrease also with Cp. Electrical measurements show that there is significant decrease in the conductivity activation energy Ea with CF for samples annealed at or below the substrate temperature TS during deposition. But for samples annealed at temperatures higher than TS, Ea was found to change back to values close to that of the unimplanted sample. A large shift to higher energy for one peak in the photoluminescence spectra at 77K has been observed, from 1.34 eV of the unimplanted sample to around 1.6 eV for the implanted samples, though with almost one order of magnitude weakening in intensity. It is also observed that ESR splitting has been induced in the fluorine implanted samples. The g-factors of the two resonances are determined to be 2.003 and 2.006, respectively. For the g=2.006 resonance, the spin density increases markedly after implantation but is essentially independent on CF before annealing and effectively reduced or eliminated after annealing. For the g=2.003 resonance, the spin density increases rapidly with CFp especially in the range from CF = 1×1020 to 1×1021 cm−3 before annealing and reduces only slightly after annealing.

The effect of fluorine implantation on the interface radiation hardness of Si-gate metal-oxide-semiconductor transistors

The radiation hardness of fluorinated SiO2/Si interface in metal-oxide-semiconductor field-effect transistors has been found to depend strongly on the amount of fluorine introduced. In this study, the fluorine was introduced by low-energy F implantation onto the surface of the polycrystalline silicon gate electrode, followed by annealing at 950 °C to diffuse F into the gate SiO2 toward the SiO2/Si interface. The improved radiation hardness is attributed to the strain relaxation near the SiO2/Si interface by fluorine incorporation.

Effects of fluorine implantation on the kinetics of dry oxidation of silicon

Kinetics of dry oxidation of silicon after implantation of fluorine in the oxide layer are investigated. It appeared that implanted fluorine can result in negative values of the linear oxidation rate constant. Fluorine profiles obtained by the nuclear reaction analysis (NRA) method using a resonant 19F(α, p)22Ne nuclear reaction will be presented. At 1200 °C the fluorine moves to the interface of Si and SiO2, both in dry oxidizing and inert atmospheres. Based on these findings, a model is presented that explains quantitatively the observed anomalous behavior of the linear oxidation rate constant.