The electrical properties of the Pb center have been measured using the conductance technique over the temperature range 130–290 K. A high concentration of Pb centers was created by vacuum annealing of 28-nm-thick thermal oxides on (111) silicon surfaces. Fitting the conductance data allowed the contribution of the (0/−) Pb level to be separated from the U-shaped background states. The (0/−) peak in the density of states was found to be asymmetrical with a broad shoulder on the conduction band side. The Pb levels were found to show a capture cross section which fell toward the band edges and which could be fitted by assuming an activated cross section with an activation energy which increased toward the band edges. By contrast, the background states showed a cross section which was temperature and band bending independent.

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4H-SiC diodes with nickel silicide (Ni2Si) and molybdenum (Mo) Schottky contacts have been fabricated and characterised at temperature up to 400°C. Room temperature boron implantation has been used to form a single zone junction termination extension. Both Ni2Si and Mo diodes revealed unchanging ideality factors and barrier heights (1.45 and 1.3 eV, respectively) at temperatures up to 400°C. Soft recoverable breakdowns were observed both in Ni2Si and Mo Schottky diodes at voltages above 1450 V and 3400 V depending on the epitaxial structure used. These values are about 76% and 94% of the ideal avalanche breakdown voltages. The Ni2Si diodes revealed positive temperature coefficients of breakdown voltage at temperature up to 240°C.

This paper presents two MMIC broadband high power amplifiers of 4 mm of periphery at the output stage in the frequency band 2-6 GHz. The amplifiers are based on AlGaN/GaN high electron mobility transistor (HEMT) technology on SiC substrate. They have been fabricated in two different european foundries: SELEX Sistemi Integrati and QINETIQ. SELEX has a gate process technology of 0.5μm, and devices of 10x100μm periphery in microstrip technology and QINETIQ has a gate-length of 0.25μm, and devices of 8x125μm in coplanar technology. The coplanar amplifier from QINETIQ has demonstrated an output power of 8W in continuous wave at V ds =20V which confirm model predictions. On the other hand, SELEX microstrip amplifier has a saturation power of 10W CW at V ds =25V and 4 GHz. This amplifier measured on-wafer in pulsed conditions exhibits a maximum power of 17W at V ds =30V.

High voltage 4H-SiC Schottky diodes with single-zone junction termination extension (JTE) have been fabricated and characterised. Commercial 4H-SiC epitaxial wafers with 10, 20 and 45 +m thick n layers (with donor concentrations of 3×1015, 8×1014 and 8×1014 cm-3, respectively) were used. Boron implants annealed under argon flow at 1500°C for 30 minutes, without any additional protection of the SiC surface, were used to form JTE’s. After annealing, the total charge in the JTE was tuned by reactive ion etching. Diodes with molybdenum Schottky contacts exhibited maximum reverse voltages of 1.45, 3.3 and 6.7 kV, representing more than 80% of the ideal avalanche breakdown voltages and corresponding to a maximum parallel-plane electric field of 1.8 MV/cm. Diodes with a contact size of 1×1 mm were formed on 10 +m thick layers (production grade) using the same device processing. Characterisation of the diodes across a quarter of a 2-inch wafer gave an average value of 1.21 eV for barrier heights and 1.18 for ideality factors. The diodes exhibited blocking voltages (defined as the maximum voltage at which reverse current does not exceed 0.1 mA) higher than 1 kV with a yield of 21 %.