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Photoinduced electron paramagnetic resonance studies performed on nominally semi-insulating, high purity 4H-SiC have revealed charge transfer from an intrinsic defect (ID) to both the shallow boron acceptor and nitrogen donor. At 4 K, incident photon energy between 1.0 and 1.7 eV produces an increase in paramagnetic boron of approximately the same magnitude as the decrease in the paramagnetic defect concentration. For T

We examine a defect in heat treated, oxidized 6H-SiC with electron paramagnetic resonance spectroscopy. Samples are examined before treatment, after oxidation, after dry (

An electron paramagnetic resonance (EPR) characterization study of isotopically enriched 12C diamond grown by General Electric has been carried out. While other commonly used techniques detect no nitrogen in this diamond, the clear EPR spectrum consistently measured a nitrogen concentration of about 0.05 ppm by calibration against a few standards. The concentration is about 2 orders of magnitude lower than that of a few natural IIa diamonds and over 4 orders of magnitude smaller than that of a typical yellow Ib diamond. The 12C diamond is evaluated to be ideal for research of diamonds under high pressure as well as irradiated diamonds. Both the experimental line shape and second moment do not support a random nitrogen distribution in this diamond. Instead, we found that nitrogen atoms tend to stay apart from one another. This uniformly dispersed nitrogen distribution is a new state of nitrogen found in diamond.

An electron paramagnetic‐resonance study of diamond films doped by implantation of phosphorus during film deposition is reported. Samples with nominal phosphorus concentration between 1016 and 1017 cm−3 exhibit two isotropic lines of equal intensity separated by 27 G. The double‐line spectrum is expected for a nuclear‐spin 1/2 species such as phosphorus. The symmetry of the center and the temperature dependence of the spin concentration suggest that phosphorus forms a substitutional shallow donor in diamond.

Germanium‐incorported oxides formed by high pressure wet oxidation of Si90Ge10 substrates are examined using electron paramagnetic resonance spectroscopy. Simulations based on the g tensor for the Ge E’ center suggest that the dominant defect observed in annealed 10 Mrad irradiated samples is an oxygen vacancy at a site of a substitutional Ge atom. Comparison of thin film and bulk samples suggests that the centers found in the films are associated with hydrogen. The results presented here should be directly applicable to optical components fabricated on semiconductor substrates for photon integrated circuits.

We have studied 50 nm Si0.8Ge0.2 buried layers and 800 nm Si0.9Ge0.1 layers, grown by molecular beam epitaxy, which were implanted with 200 keV oxygen O+ ions to a dose of 1.8×1018/cm2. This implantation procedure is similar to that used in the formation of SIMOX (separation by implantation of oxygen), although it was not followed by the usual high temperature anneal. Because the initial implantation profile extends as far as 600 nm below the Si surface, the 50 nm Si0.8Ge0.2 layers were embedded in Si at depths of 600, 500, 400, and 300 nm from the Si surface. The effects of Ge incorporation could then be studied as a function of distance from the surface and position within the implantation profile. Using a scanning transmission electron microscope equipped with energy dispersive x‐ray spectroscopy, we examined cross‐sectional specimens for the distribution of the Ge in and around the implanted oxide layer. We found that the Ge tended to be excluded from the oxide in all the samples with the 50 nm buried layer. For the case where the oxide was implanted into the midst of an 800 nm layer, the Ge remained in the oxide.

In oxides fabricated by thermal oxidation or ion implantation, an order‐of‐magnitude increase is observed in the concentration of radiation‐induced E’ centers when the oxide is first exposed to H2 at temperatures greater than 600 °C. To the authors’ knowledge, we report the first data indicating that preirradiation hydrogen annealing of thermal oxides causes a large increase in the concentration of radiation‐induced E’ centers. We discuss evidence suggesting that the hydrogen anneal creates a new E’ precursor, Si—H, from Si—Si bonds.

An electron trapping instability in silicon dioxide films sputtered onto silicon substrates was analyzed by metal‐oxide‐semiconductor electrical methods and electron paramagnetic resonance (EPR), and was compared with an E’ defect model from molecular orbital cluster calculations. This comparison indicates that an E’ defect may well be responsible for the observed trapping instability, since electrically measured trap filling and emptying was quantitatively correlated with a reversible variation in the EPR signal magnitude. The specific model proposed for this defect is a ‘‘surface‐like’’ or hemi‐E’ center, O3≡Si−, which upon loss of an electron becomes O3≡Si+ and relaxes towards a planar configuration. The relaxation energy associated with the restoration of the original configuration is manifested as a hysteresis in the electrical trap filling and emptying cycle.