Remarkable p-type activation of heavily doped diamond accomplished by boron ion implantation at room temperature and subsequent annealing at relatively low temperatures of 1150 and 1300 °C

We have obtained ultrahigh room-temperature (RT) hole Hall and effective mobility in Si0.3Ge0.7/Ge/Si0.3Ge0.7 heterostructures with very small parallel conduction. Reducing parallel conduction was achieved by employing Sb doping in Si0.3Ge0.7 buffer layers, which drastically increased RT hole Hall mobility up to 2100 cm2/V s in the strained Ge channel modulation-doped structures and improved device characteristics of the p-type metal–oxide–semiconductor field-effect transistors with the strained Ge channel. The peak effective mobility reached to 2700 cm2/V s at RT, which was much higher than the bulk Ge drift mobility.

Nitrogen-doped (N-doped) p-type ZnTe films have been prepared on GaAs(100) substrates by hot wall epitaxy (HWE) for the first time. To obtain high-quality films with high hole concentrations, optimum growth conditions such as the substrate temperature and the growth rate were studied by X-ray and Photoluminescence (PL) measurements. The hole concentration and Hall mobility were 1.1×1017 cm-3 and 52 cm2 V-1 s-1, respectively. The PL spectra of these films had a excitonic emission (I1), indicating high crystalline quality. The activation energy of the nitrogen acceptor was calculated, for the first time, to be 51 meV from the donor-acceptor (DA) emission energy. The existence of nitrogen in the films was confirmed by secondary ion mass spectroscopy (SIMS). The N-doped ZnTe-ZnSe SL's were also prepared and the hole concentration and Hall mobility were 2.3×1018 cm-3 and 36 cm2 V-1 s-1, respectively.

The effects of boron and argon ion implantation on the tribological characteristics of SUS440C stainless steel, sliding against a SUS440C ball (unimplanted) were investigated at room temperature using a friction test apparatus employing a ball-plate geometry in the absence of a lubricant. Wear performance was estimated using a profilometer tracing of the specimen wear track. Boron implantation reduced both the friction and wear of SUS440C. The friction coefficient of SUS440C was reduced from 0.75 to 0.15. SEM observations of wear track topography suggest that the reduction of the friction coefficient can be attributed to reduced adhesion due to boron implantation. The friction coefficient of the boron implanted layer decreased with an increase in the total ion dose. Argon implantation was carried out to distinguish the effects of implantation from the influence of contamination. Argon implantation increased the friction coefficient from 0.8 to 1.0 in contrast with boron implantation.

Temperature-dependent Hall analysis of carbon-doped GaAs

Formation of amorphous and crystalline phases in the ion beam modified boron-iron system studied by Mössbauer spectroscopy

Solution growth of high quality P-Type β-FeSi 2 single crystals using Zn-solvent

Crystal growth of β-FeSi 2 by temperature gradient solution growth method using Zn solvent

To obtain p‐type doping of diamond through B ion implantation, thermal treatments are necessary to reconstruct the diamond lattice and to locate B atoms in substitutional lattice positions. The present contribution evaluates by STEM‐EELS and CL spectroscopy the amorphisation of diamond lattice under the B+ bombardment and its subsequent reconstruction after the thermal treatment. In addition, TEM observations allowed localizing the boron spatial distribution. Carbon‐related peaks of EELS spectroscopy shows a nearly complete recovery of the diamond lattice after thermal treatment. Indeed, at 1600 °C, sp2/sp3 ratio in implanted regions changes from 0.56 to 0.18 (0.15 value was measured before implantation). On the other hand, CL spectroscopy reveals how A‐Band and free exciton emission peaks, which are quenched by B+ implantation, recover after annealing. Boron ion implantation was used to create ohmic contacts in two different diamond samples, treated with different annealing velocities. Crystalline reconstruction, evidenced by TEM data explains the related electric behaviour. Nanoscale evidences of amorphisation, lattice reconstruction and dopant activation are presented and discussed in this work.

Near-band-edge cathodoluminescence of doped diamonds was studied at low temperatures. The doped diamonds were prepared either during the CVD growth of the diamond films by adding boron, phosphorus, or lithium sources to the reaction gases, or alternatively by ion implantation of boron, phosphorus, sodium, or arsenic. Observation of the boron bound exciton after boron implantation and annealing above 1200 °C is taken as evidence that this acceptor species was successfully incorporated on substitutional lattice sites. Similarly, doping by phosphorus either during growth or by ion implantation and subsequent annealing leads to the emission of a bound exciton transition at 5.175 eV. Assuming Haynes' rule to be valid we estimate a donor ionization energy of nearly 640 meV for the phosphorus-related impurity. Discrete donor–acceptor pair transitions are observed in the near-band-edge region in diamonds which contain both phosphorus and boron in low concentrations. The analysis of the spectra yields 630 meV activation energy of the phosphorus-related donor consistent with the estimate from the bound exciton spectra.

Surface investigations on annealed and boron implanted Fe80Mo7B12Cu1 amorphous ribbons

High-quality B-doped homoepitaxial diamond films have been synthesized by microwave plasma chemical-vapor-deposition (CVD) using a mixture consisting of CH4, H2, and trimethylboron B(CH3)3 diluted by H2 gas. These films have been obtained on the basis of the approach that high-quality diamond films should be grown in a clean CVD system. Hall-effect measurements of the film show that the Hall mobility exceeds about 1800 cm2/V·s when the hole concentration is 2.3×1014 cm-3 at room temperature (290 K) and about 3300 cm2/V·s at 170 K. These results indicate that the quality of the present B-doped CVD films is comparable with or better than that of high-quality natural diamonds.

Multicharged ions born and barium ions were used to perform interfacial treatment of the SiC/SiO2 interface. A Q-switched Nd:YAG laser (wavelength λ = 1064 nm, pulse width τ = 7 ns, and fluence F = 135 J/cm2) was used to ablate boron and barium targets to generate multicharged ions. Time-of-flight and three-grid retarding field ion energy analyzer were used to detect the charge state and the ion kinetic energy. Fully stripped boron ions are generated. The ions were deflected by an electrostatic field to separate them from the neutrals. SRIM simulation was used to estimate the ion penetration depth in the SiC substrate. The multicharged ions were used for shallow ion implantation in 4H SiC. The optical bandgap of the 4H SiC was reduced due to boron ion implantation. Several MOSCAP devices were fabricated with combination of boron and barium shallow implantation. High-low C-V measurements were used to characterize the MOSCAPs. Boron implantation affects the flatband voltage significantly, while the effect of barium ion implantation is negligible. Shallow boron implantation in the SiC/SiO2 interface reduces the flatband voltage from 4.5 to 0.04 V.

Continuous and highly oriented β-FeSi2 films were prepared on Si (111) substrates at 700–760°C by use of a RF magnetron sputtering deposition with a Fe target. An inserted low temperature (450°C) initial layer and post-annealing were effective in improving the crystal quality characterized by the widths of X-rays rocking curve (ω scan) and the photoluminescence intensity. As grown β-FeSi2 films with a full width at half maximum of 15 arcmin were obtained and 1.58 µm photoluminescence at room temperature was clearly observed from the 800°C annealed films. The as-grown films were p-type, with a hole concentration and a Hall mobility about 2×1018 cm-3 and 20 cm2/V·s respectively. A conduction type change took place after thermal annealing in N2 at 890°C for 20 hours, resulting in a electron concentration of 5×1016 cm-3 and a mobility up to 230 cm2/V·s, while a p-type conduction with a diminished hole concentration and a increased mobility, still remained after thermal annealing at 800°C.

Polycrystalline diamond films, heavily implanted with boron ions (2×1016 cm−2, 60 keV) are found to exhibit, following annealing and graphite removal, electrical properties similar to those obtained for chemical vapor deposited diamond, heavily doped with B during film growth. Control experiments in which carbon ions were implanted and annealed under identical conditions did not show any significant electrical conductivity, verifying that the measured effects are caused by chemical doping due to the presence of B. It is therefore concluded that doping of polycrystalline diamond by ion implantation is possible and graphitization along grain boundaries, that one might have expected to occur as a result of implantation and annealing, does not seem to severely affect the electrical properties of the implantation-doped material.

Electron microscopy profiling of ion implantation damage in diamond: Dependence on fluence and annealing