A high powersemiconductor device with integral heat sink capable of accommodating substantial heat flux on the order of one kw per cm.sup.2. Theintegral heat sink is formed on the active surface of the semiconductor and utilizes an AlN thin film of high purity to provide a low thermal impedance heatconductor for removing heat directly from the active semiconductor surface. A microchannel heat sink is formed on the A1N thin film and has a source of cooling fluid flowing through the microchannel heat sink for conducting heat away from thesink. The result is the ability to conduct large heat fluxes away from the intimately contacted heat generating semiconductor surface to the cooling fluid in the microchannel heat sink and thus operate the semiconductor under substantially higher power than has been practical heretofore in a device of such simplicity.
This work showed that modeling the lifetimes of powersemiconductor devices with Bayesian LMs is possible, but restricted to a speciﬁc range, where tested devices have the same failure mechanisms. Expanding the prediction range showed the poor extrapolation quality of the model for tests with probably other failure mechanisms. As a step of improvement a Bayesian LM with mixed distri- butions was used, but no signiﬁcant increase in quality could have been observed, hence further improvements and/or other model assumptions are needed.
Powersemiconductor devices are used to control the energy transfer of electrical and electronic systems. For last 5 decades Silicon (Si) was a dominant powersemiconductor material. It had several advantages over Germanium and Selenium. Si opened new applications which were not physically possible with previous materials. It was more reliable than previous materials. It was easy to use and is a low cost material. Now that the energy requirement is growing continuously, we need to develop high power, high efficiency, and high power density applications for power transfer. Si based devices are approaching their limits for high voltage and high frequency applications. Currently, Si IGBTs (Insulated gate bipolar transistor) can handle voltage of 5 kV and current of 1000 A but the operating frequency is limited to maximum of 100 kHz . It reduces the efficiency and makes integration of system more difficult. Also, because of low frequency operation, a bulky filter circuit is required which increases system size and cost. Also, bulky cooling system is required to dissipate the heat generated because of high energy losses. On the other hand, Si MOSFETs have high on resistance which causes high conduction loss at high voltages limiting the use of these MOSFETs for low and medium voltages (< 600 V). The junction temperature of 150°C limits the use of Si devices in high temperature and high power density applications .
This dissertation also presents a simple physics-based power Schottky diode model which is comprised of a voltage controlled current source, a temperature dependent drift region resistance and a nonlinear capacitance. A detailed parameter extraction procedure for this model is also discussed in this work. The developed procedure includes the extraction of doping concentration, active area and thickness of drift region, which are needed in the power Schottky diode model. The main advantage is that the developed procedure does not require any knowledge of device fabrication, which is usually not available to circuit designers. The only measurements required for the parameter extraction are a simple static I-V characterization and C-V measurements. Furthermore, the physics-based SiC Schottky diode model is also temperature dependent and is generally applicable to SiC Schottky diodes. This procedure is demonstrated for four different Schottky diodes from two different manufacturers. The parameter extraction procedure represents an original contribution in the area of characterization of powersemiconductor devices.
which are already known in the design, manufacture and use of powersemiconductor devices and component parts thereof and which may be used instead of or in addition to features already described herein. Features of one embodiment may be replaced or supplemented by features of another embodiment. For example, the interfacial layer of the second powersemiconductor device may be used in combination with the linear 5
Participants were recruited to participate in a project including longitudinal studies of the development of FXS at the University of North Carolina at Chapel Hill. The aim of the larger project was concerned with investigating the cognitive, behavioral, and psychological trajectories of children with FXS. Data for the current sample were pulled from two studies associated with previously mentioned project in order to address the longitudinal research questions of the study. The first study included boys with FXS who were seen every twelve months for an assessment (n=20). The second study included boys with FXS and typically developing boys seen every eighteen months for assessment (FXS n= 13; TD n= 17). Participants’ data were pulled from the relevant assessment ages, between ages 3 to 4 for the initial assessment (“preschool age”) and then again between ages 5 to 6 for the subsequent assessment (“school entry”). Subjects were used from both samples to increase the power of the potential findings in the analyses.
namely the distributions of them and discovered that they have power-law tails. This phenomenon has later been observed in many naturally occurring networks, and a network with such a degree distribution is referred to as a “scale-free network.” In 1976, he published another paper which proposed an explanation for the existence of power-laws in certain networks. This explanation has been widely accepted and adopted and is known today as “preferential attachment” . The explanation claims that “citations receive further citations in proportion to the number they already have” , page 18. Thus vertices with a large degree are more likely to accumulate more neighbors. Preferential attachment and scale-free networks are notions of much interest in network science today , page 17-18.
In considering the question of “why voting on Indian issues adhered so closely to partisan lines” I have attempted to interpret it though several, feasible analytical queries: to what extent did Indian Removal debate, and the pro-Removal discourse it generated, furnish a platform for the articulation of a national identity, and a story, by Jackson and the Democratic party?—to what extent did this story help to distinguish them from their political opponents, who stood as antagonists in their story of the nation’s true destiny? Most basically, to what extent did the arguments constructed to support Removal aid in the conceptual seduction—for a political party is an engine of power whose fuel is popularity—that contributed to the growth and popularity of the story being created by the Democratic party? In short, why were Jackson and his party victorious, both in Indian Removal, and, really in reshaping the political landscape? Ultimately, I contend, the question of “how Indian Removal was justified” and why “Jacksonian populism succeeded so profoundly” are in fact the same question.
studio framework. This software package allows for code to be developed in a simulation environment before being applied directly to the hardware. Once the binary file has been compiled from C code, the targeted cores from the DSP system are then connected and the binary file loaded. For any memory needs, such as loading the index data and short reads into memory, a memory browser is used to load directly to the memory architectures available. The selected cores may then be executed to run the loaded binary instructions. In a production environment, the short reads would be able to be transferred through one of the DSP’s many high throughput communication modules available. This system of streaming short reads from the NGS frees up additional memory from the DSP. Unlike alternate coprocessors, the design of the DSP allows for an implementation to entirely run on a self-contained board. The Advantech board used in this thesis requires that power be supplied over a PCI Express connection provided by a computer, but no other functionality is used from that connection. Ideally, testing would be completed with an alternate power source and the board would operate outside of a computer environment, but precise power measurements are still able to be obtained for testing purposes of this thesis.
The substitution of In 3+ at the M site in these materials causes the excitation band to shift near 400 nm, which causes these materials to be used as potential LED phosphors without the use of rare earth ions. The ions Al 3+ , Ga 3+ , and In 3+ occupy the M site simultaneously, which is a remarkable feat. The increased substitution of In 3+ causes the PL emission to be quenched, therefore substitutions where x ≤ 0.025 are ideal for phosphor material with an appreciable PL intensity. The increase in the temperature of the reducing atmosphere causes the PL emission to change from orange-yellow to a green-yellow color. This information is important since it is known that the combination of a blue emitting In x Ga 1-x N semiconductor combined with a yellow emitting phosphor