The electrical conductivity of single crystals of rutile was measured in the “c” and “a” directions over the temperature range 1000°–1500°C and from 1 to 10−15 atm of oxygen. Based on the excellent fit observed between the theoretically derived relation σ5=false(Aσ+Bfalse)Pnormalo2−1+I′ σ3 and the experimental conductivity data, the nonstoichiometric defect structure of rutile was rationalized in terms of quasi‐free electrons and both triply and quadruply ionized titanium interstitials. In addition, this equation satisfies a contribution due to impurity conduction where I′ is proportional to a temperature dependent concentration of ionized impurities or a contribution due to intrinsic conduction where I′ is proportional to a temperature dependent concentration of holes in the valance band.The standard enthalpy of formation for the following defect reactions in rutile normalTi+2O=O2false(normalgfalse)+Tii+3+3e;normalΔHao=9.6±0.2 normalev false(afalse) normalTi+2O=O2false(normalgfalse)+Tii+4+4e;normalΔHbo=10.8±0.2 normalevfalse(bfalse) Tii+3=Tii+4+e;normalΔHco=1.2±0.4 normalevfalse(cfalse) I=I++e;normalΔHdo=3.7±0.2 normalev false(dfalse) were determined from the temperature dependence of A , B , and I′ obtained from the above relation and from the experimental expression for the temperature dependence of electron mobility. The values of normalΔHao , normalΔHbo , and normalΔHco are in agreement, within experimental error, with those obtained in an earlier investigation based on conductivity measurements in the c direction only. If impurity conduction is involved, normalΔHdo is equal to the standard enthalpy of formation for the ionization of an impurity. If intrinsic conduction is involved, normalΔHdo is equal to the band gap energy which is thought to be between 3 and 4 ev for rutile. The ratio of electrical conductivities for the c and a direction is essentially independent of oxygen pressure above 1100°C; but at the lower temperatures, 1000° and 1100°C, the ratio is dependent on pressure in contradiction to the initial assumption that mobility is a function of temperature only.

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Circuit camouflage technologies can be integrated into standard logic cell developments using traditional CAD tools. Camouflaged logic cells are integrated into a typical design flow using standard front end and back end models. Camouflaged logic cells obfuscate a circuit's function by introducing subtle cell design changes at the GDS level. The logic function of a camouflaged logic cell is extremely difficult to determine through silicon imaging analysis preventing netlist extraction, clones and counterfeits. The application of circuit camouflage as part of a customer's design flow can protect hardware IP from reverse engineering. Camouflage fill techniques further inhibit Trojan circuit insertion by completely filling the design with realistic circuitry that does not affect the primary design function. All unused silicon appears to be functional circuitry, so an attacker cannot find space to insert a Trojan circuit. The integration of circuit camouflage techniques is compatible with standard chip design flows and EDA tools, and ICs using such techniques have been successfully employed in high-attack commercial and government segments. Protected under issued and pending patents. General TermsSecurity, Design.

We report the first transmission electron microscopy (TEM) study of a HgTe-CdTe superlattice. The superlattice consists of 250 layer pairs of HgTe-CdTe on a (100) CdTe substrate and was grown at 175 °C by molecular beam epitaxy. Vertical cross-section TEM images show a highly regular structure of the superlattice from the CdTe substrate to the free surface, indicating that interdiffusion effects at interfaces are minimal. Diffraction patterns taken from the first 30 pairs of layers of the superlattice from the CdTe buffer layer show a series of satellite spots up to the sixth order. This implies that the interfacial sharpness of this HgTe-CdTe superlattice is comparable to those interfaces of high quality III-V semiconductor superlattices. The HgTe-CdTe superlattice exhibits an infrared photoluminescence peak at 357 meV, in reasonable agreement with theoretical predictions of its band gap.

Strong evidence is presented that the X-level defect, which produces a 0.111-eV acceptor level in Si : In, is a substitional In–substitutional C (Ins-Cs) pair. The concentration of this defect follows a mass-action law with the In and C concentrations, the association constant being (1.4±0.3) ×10−19 cm−3 at 650 °C. Reversible changes in the X-level concentration between anneal temperatures of 650 and 850 °C are observed, and a pair binding energy of 0.7±0.1 eV is estimated. The electronic properties and temperature dependence of the concentration of this center are found to be those expected for a nearest-neighbor Ins-Cs pair.