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The aim of this analysis was to investigate the impact of tumour-, treatment- and patient-related cofactors on local control and survival after postoperative adjuvant radiotherapy in patients with non-small cell lung cancer (NSCLC), with special focus on waiting and overall treatment times. For 100 NSCLC patients who had received postoperative radiotherapy, overall, relapse-free and metastases-free survival was retrospectively analysed using Kaplan-Meier methods. The impact of tumour-, treatment- and patient-related cofactors on treatment outcome was evaluated in uni- and multivariate Cox regression analysis. No statistically significant difference between the survival curves of the groups with a short versus a long time interval between surgery and radiotherapy could be shown in uni- or multivariate analysis. Multivariate analysis revealed a significant decrease in overall survival times for patients with prolonged overall radiotherapy treatment times exceeding 42 days (16 vs. 36 months) and for patients with radiation-induced pneumonitis (8 vs. 29 months). Radiation-induced pneumonitis and prolonged radiation treatment times significantly reduced overall survival after adjuvant radiotherapy in NSCLC patients. The negative impact of a longer radiotherapy treatment time could be shown for the first time in an adjuvant setting. The hypothesis of a negative impact of longer waiting times prior to commencement of adjuvant radiotherapy could not be confirmed.

To potentially improve device performance, we attempted to grow gallium nitride (GaN) films with better crystalline quality (fewer mismatch dislocations) using a tantalum carbide (TaC) substrate, which is more closely lattice matched to GaN than currently used substrates. We created the TaC substrate, using pulse laser deposition (PLD) of TaC onto (0001) SiC substrates at tilde 1000 deg C, and grew GaN films, using metal organic chemical vapor deposition (MOCVD). Using x-ray diffraction, we determined the TaC films grown on-axis were higher quality than the off-axis films, but the latter could be improved to a comparable quality by annealing at 1200-1600 deg C for 30 min. We also deposited GaN films onto the TaC after it had been nitrided with NH3 for 3 min at 1100 deg C and used aluminum nitride (AlN) as a low temperature nucleation layer. Using these methods, the crystalline quality of the GaN films was higher - the grains were tilde 10 times larger than those typically seen in films grown on SiC or sapphire, and they contained more than an order of magnitude fewer dislocations compared to a typical value of 4 x 10(exp 9) sq cm. However, the grains lacked the required (0001) texture, producing a very rough surface., The original document contains color images. Prepared in collaboration with Bluewave, Inc. and the Physics Dept. of Univ. of MD.

The activation of dopants for wide band-gap semiconductors such as SiC is a subject of much research. Silicon Carbide is problematic as Si sublimates from the SiC matrix at the temperatures required for activation. We have investigated the success of capping SiC substrates with more thermally stabile materials to impede Si sublimation. We present data taken from the SiC capping strategies using carbon and AlN/BN surface caps. We found that the C cap protects the surface at all analyzed annealing temperatures. While the nitride cap protects the surface at all temperatures, however, it was very difficult to remove. There were modest increases in the sheet resistance for the C capped material when compared to the nitride capped material with the exception of the graphite capped 1800 degree sample., Prepared in collaboration with the Electrical Engineering Deparment, University of South Carolina, Columbia, SC and the Physics Department, University of Maryland, College Park, MD. Presented at the Army Science Conference (25th), "Transformational Army Science and Technology - Charting the future of S&T for the Soldier," held in Orlando, Florida on 27-30 Nov 2006. Published in proceedings of the same. See also ADM002075. The original document contains color images.

We show how defects in semiconductor device structures are formed, how they can affect the properties and reliability of devices, and how they might be avoided. Examples will be drawn from wide band gap semiconductor materials and devices we have fabricated in-house or examined for DARPA, collaborators in the P&E CTA, a power electronics MTO, or an SBIR., See also ADM002075., The original document contains color images.

High temperature superconductor (HTSC) microbolometers are highly sensitive thermal detectors that can be miniaturized for affordable passive millimeter-wave (MMW) imaging. When coupled to a micro-antenna and built into an imaging system, they are most promising for pilotage in fog, clouds, and smoke. A completely dry etch process is described for fabricating resistive-edge microbolometers based on YBa2Cu3O7 (YBCO)., See also ADM002075. The original document contains color images. Presented at the Army Science Conference (25th) held in Orlando, FL on 27-30 November 2006.