Аналіз впливу роботи пристроїв контактної зварки на параметри напруги мережі

Three fully integrated bandgap voltage references (BGVRs) have been demonstrated in a 4H-SiC bipolar technology. The circuits have been characterized over a wide temperature range from 25 degrees C to 500 degrees C. The three BGVRs are functional and exhibit 46 ppm/degrees C, 131 ppm/degrees C, and 120 ppm/degrees C output voltage variations from 25 degrees C up to 500 degrees C. This letter shows that SiC bipolar BGVRs are capable of providing stable voltage references over a wide temperature range.QC 20160311HOTSi

Destroying the Panthers: The Effect of Allied Combat Action on I./SS Panzer Regiment 12 in Normandy, 1944

This article is an examination of the operational record of the World War Two German Panther tank during the Normandy Campaign of summer 1944. Challenging its perception as mechanically unreliable, this article argues Allied combat action was responsible for a large percentage of Panthers that were out of action. Secondly, the inferior resources of the German tank replacement and repair program were no match for superior Canadian Army practices during 1944. To support these arguments the author examines Canadian and German wartime primary documents as well as multiple secondary sources

El juego de los dioses : Un viaje a través del olimpismo

A través de una profunda investigación por más de 150 fuentes diversas, El juego de los dioses: Un viaje a través del olimpismo traza un recorrido por los orígenes, historia y curiosidades de los Juegos Olímpicos, desde su comienzo en la antigua Grecia hasta la actualidad. Instantes de gloria, finales escandalosas, los vaivenes políticos que afectaron cada edición, el crecimiento deportivo y monetario de los últimos 30 años, y la explosión mediática de un evento que paraliza al mundo son parte de los temas que hacen a la historia de los Juegos Olímpicos. Se trata de la máxima competencia deportiva del mundo moderno, donde los atletas de todo el planeta participan en un gran número de pruebas que ponen en juego las tan ansiadas medallas de oro, plata y bronce.Editorial de la Universidad Nacional de La Plat

Silicon dioxide and aluminium nitride as gate dielectric for high temperature and high power silicon carbide MOSFETs

Silicon carbide (SIC) is a wide bandgap semiconductor thathas been suggested as a replacement for silicon in applicationsusing high voltages, high frequencies, high temperatures orcombinations thereof. Several basic process steps need to bedeveloped for reliable manufacturing of long-term stableelectronic devices. One important process step is the formationof an insulator on the silicon carbide surface that may be usedas a) a gate dielectric, b) for device isolation or c) forpassivation of the surface. Silicon dioxide and aluminumnitride have been suggested for these purposes. This thesiscovers the investigation of some formation methods for boththese materials on 4H and 6H silicon carbide, and theelectrical characterisation of the resulting films. Commercially available n-type and p-type 4H and 6H SICwafers have been used, and both the silicon face and the carbonface have been investigated. Silicon dioxide has been formed byseveral methods: a) dry thermal oxidation with or without theaddition of TCA (trichloroethane), b) wet oxidation inpyrogenic steam or with awater bubbler, c) oxide deposition byPECVD (plasma enhanced chemical vapor deposition) or LPCVD (lowpressure chemical vapor deposition) and d) oxidation of aevaporated or LPCVD deposited sacrificial layer of silicon. Theinfluence of various cleaning methods prior to oxidation hasbeen studied, as well as post-oxidation and post-metallisationannealing. The aluminum nitride films were grown by MOCVD(metal organic chemical vapor deposition) under various processconditions. Oxidation kinetics have been studied for dry thermaloxidation at 1200 0C. The redistribution of aluminum (p-typedopant in SiC) during dry thermal oxidation has beeninvestigated using SIMS (secondary ion mass spectrometry). Themorphology of the aluminum nitride was determined using x-raydiffraction rocking curves, RHEED (reflection high energyelectron diffraction) and AFM (atomic force microscopy). Thequality of the silicon dioxide used as gate dielectric has beendetermined using breakdown field measurements. High frequencycapacitance-voltage measurements have been used on bothinsulators to a) verify thickness measurements made with othermethods, b) to determine fixed oxide charges by measuring theflatband voltage shifts and c) to quantitatively compare theamount of interface states. For electrical characterisation either aluminum, titanium ordoped polysilicon circular gate contacts of various sizes wereformed on the insulator surface. Flat MOS capacitors weremainly used for the electrical characterisation. U-grooved MOScapacitors, manufactured by RIE (reactive ion etching), wereused to test the quality of oxides grown on vertical surfaces.Two types of MOSFETs (metal oxide semiconductor field effecttransistors) have been fabricated: vertical U-grooved andlateral devices. Keywords:silicon carbide, thermal oxidation, silicondioxide, metal organic chemical vapor deposition (MOCVD),aluminum nitride, capacitance-voltage measurements, MOSFET.NR 2014080

Silicon dioxide and aluminium nitride as gate dielectric for high temperature and high power silicon carbide MOSFETs

Silicon carbide (SIC) is a wide bandgap semiconductor thathas been suggested as a replacement for silicon in applicationsusing high voltages, high frequencies, high temperatures orcombinations thereof. Several basic process steps need to bedeveloped for reliable manufacturing of long-term stableelectronic devices. One important process step is the formationof an insulator on the silicon carbide surface that may be usedas a) a gate dielectric, b) for device isolation or c) forpassivation of the surface. Silicon dioxide and aluminumnitride have been suggested for these purposes. This thesiscovers the investigation of some formation methods for boththese materials on 4H and 6H silicon carbide, and theelectrical characterisation of the resulting films. Commercially available n-type and p-type 4H and 6H SICwafers have been used, and both the silicon face and the carbonface have been investigated. Silicon dioxide has been formed byseveral methods: a) dry thermal oxidation with or without theaddition of TCA (trichloroethane), b) wet oxidation inpyrogenic steam or with awater bubbler, c) oxide deposition byPECVD (plasma enhanced chemical vapor deposition) or LPCVD (lowpressure chemical vapor deposition) and d) oxidation of aevaporated or LPCVD deposited sacrificial layer of silicon. Theinfluence of various cleaning methods prior to oxidation hasbeen studied, as well as post-oxidation and post-metallisationannealing. The aluminum nitride films were grown by MOCVD(metal organic chemical vapor deposition) under various processconditions. Oxidation kinetics have been studied for dry thermaloxidation at 1200 0C. The redistribution of aluminum (p-typedopant in SiC) during dry thermal oxidation has beeninvestigated using SIMS (secondary ion mass spectrometry). Themorphology of the aluminum nitride was determined using x-raydiffraction rocking curves, RHEED (reflection high energyelectron diffraction) and AFM (atomic force microscopy). Thequality of the silicon dioxide used as gate dielectric has beendetermined using breakdown field measurements. High frequencycapacitance-voltage measurements have been used on bothinsulators to a) verify thickness measurements made with othermethods, b) to determine fixed oxide charges by measuring theflatband voltage shifts and c) to quantitatively compare theamount of interface states. For electrical characterisation either aluminum, titanium ordoped polysilicon circular gate contacts of various sizes wereformed on the insulator surface. Flat MOS capacitors weremainly used for the electrical characterisation. U-grooved MOScapacitors, manufactured by RIE (reactive ion etching), wereused to test the quality of oxides grown on vertical surfaces.Two types of MOSFETs (metal oxide semiconductor field effecttransistors) have been fabricated: vertical U-grooved andlateral devices. Keywords:silicon carbide, thermal oxidation, silicondioxide, metal organic chemical vapor deposition (MOCVD),aluminum nitride, capacitance-voltage measurements, MOSFET.NR 2014080

Sputtered Ohmic Cobalt Silicide Contacts to 4H-SiC

Ohmic CoSi2 contacts to n-type 4H-SiC showing low contact resistance have been made by sputter depositing sequential layers of Si and Co on 4H-SiC substrates followed by a two-step rapid thermal anneal at 600 °C and 950 °C. The contacts formed have been characterized at temperatures ranging from-40 °C to 500 °C with a specific contact resistance of 3.80∙10-5 Ωcm2 at 25 °C and a minimum of 6.0∙10-6 Ωcm2 at 500 °C.QC 20160314SSF HOTSi

Design and characterization of 500°c schmitt trigger in 4H-SiC

Two versions of Schmitt trigger, an emitter-coupled and an operational amplifier (opamp)-based, are implemented in 4H-SiC bipolar technology and tested up to 500 °C. The former benefits the simplicity, smaller footprint, and fewer number of devices, whereas the latter provides better promise for high temperature applications, thanks to its more stable temperature characteristics. In addition, the measurements in the range 25 °C - 500 °C, shows that the opamp-based version provides negative and positive slew rates of 4.8 V/μs and 8.3 V/μs, ~8 and ~3 times higher than that of the emitter-coupled version, which are 1.7 V/μs and 1 V/μs.QC 20160309SSF HOTSi