Browsing by Subject "Semiconductor switches"
Now showing 1 - 6 of 6
Results Per Page
Sort Options
Item A Photo-Initiated Self-Sustaining Conduction State in Semi-Insulating GaAs(Texas Tech University, 1984-05) Jiang, ChunHigh power switching using GaAs:Cr and undoped GaAs initiated by 1.06 micrometer YAG laser and 0.5 micrometer DYE laser at liquid nitrogen temperature was demonstrated. Some unusual properties of photoconductivity, such as the negative differential motility and the change of the relaxation time of the induced carriers due to the different intensity of light injection, have been investigated. For field strength above 20 kv/cm a self-sustaining conduction state was observed, following the photoconductive current pulse with a delay of 1-UOO ns. Various features of this second signal are presented. In order to understand the mechanism responsible for the self-sustaining conduction state, a heating model was investigated analytically and found to be inadequate. Possible mechanisms are discussed.Item Contact effects in light activated GaAs switches(Texas Tech University, 1985-05) Durkin, Peter SNot availableItem Effects of gate current on conduction modulation in pulsed power thyristors(Texas Tech University, 2001-05) Brito, Efren LujanTexas Tech, in conjunction with PTS Company, has studied some of the device parameters of PTS's Pulse Power Thyristors(PPT), especially thePPT5325. The objective of this work was to establish the di/dt, turn-on, and reverse recovery characteristics of the PPT with varying gate drive current and anode voltage and are more specifically stated below: 1. Determine if varying gate current will improve turn-on times, 2. Determine if pulling charge from the gate will improve turn-off times and lower reverse voltages, 3. Determine the reverse recovery times, 4. Determine if the reverse recovery times can be improved by removing excess charge carriers, or plasma, from the gate with varying gate voltage, 5. Compare the PPT5325 with other pulsed power thyristors. The PPT was tested using a constant current gate drive circuit having a rise time of approximately 250ns, pulse width of lOus, and a maximum of 500A. A capacitive discharge circuit was used with anode-cathode voltages varying from OV to 1.2kV. The anode circuit is also capable of reapplying a reverse anode voltage at a specified time. This paper describes the necessary methods in designing these test circuits to obtain the device characteristics just explained.Item Electron beam controlled switching(Texas Tech University, 1995-05) Awrach, James MichaelNot availableItem Fast transient behavior of thyristor switches(Texas Tech University, 1985-12) Hudgins, Jerry LynnThe fast pulse switching behavior of center-fired and interdigitated thyristors was studied by switching 10 us, 1000 A (at 800 V) pulses. Single-shot switching was performed up to 10,000 A/us, and repetitive switching at 500 Hz and 800 Hz up to 10,000 A/us for various lengths of time. No damage to the devices resulted from the switching stresses.Item Statistical analysis of the digital micromirror devices hinge sag phenomenon(Texas Tech University, 2002-05) Rahman, Mohammed MainurThe use of integrated circuit processing technology in order to manufacture Microelectromechanical systems is a relatively recent field of research. Texas Instruments, DLP™ has been the leader in optical MEMS devices, by inventing a commercially viable means of MEMS for projection displays. This thesis starts with a brief introduction to the DMD™ device, which is the heart of DLP™ technology. Then it gives a brief overview of hinge-related failures. The main objective of the thesis is to establish a relationship between hinge thickness, pre-bake temperature, and hinge sag in DMD™ devices. In order to achieve the goals of the thesis a Design of Experiments has been performed. The step-by-step approach of the experiment, the collection of data, and a detailed analysis of the results have been discussed in the thesis.