Barry Mana Singer

Comparison of high voltage devices for power integrated circuits

A variety of lateral high voltage devices has been investigated for applications in power ICs, including RESURFed LDMOS transistors, merged bipolar-MOS transistors (LBMOS) and insulated gate rectifiers (LIGR). The devices are described and compared on the basis of current handling capability and switching speed. It is shown that for low load currents, the LDMOS exhibits superior performance, while for high load currents, the LIGR is advantageous, and the LBMOS shows only marginal improvement over the LDMOS at current gain of 5. In terms of switching, the LBMOS switches in 1-3 µsec, the LIGR in 3-10 µsec, and the LDMOS in tens of nsec. depending on the bias condition. The role of the substrate in lateral devices is also discussed.

Integral equation method for computer evaluation of electron optics

A Greens function technique for the computation of electric potentials in electrostatic systems of arbitrary configuration, especially with cylindrical symmetry, is developed. The system may include open boundaries and dielectric media. The integral equation is numerically solved by iteration. Its convergence is very fast. Computer calculated field and potential values are of high accuracy (usually better than 10-4). Errors in electron optical data, derived from trajectory computation, were found to be within fabrication tolerances of experimental systems. The computerized method proved to be an excellent tool for the design of electron optical systems, as electron image intensifiers.

Design of high-density power lateral DMOS transistors

Significant reduction in the surface area required for high voltage lateral DMOS transistors (LDMOSTs) has been achieved. Application of a recently developed field shaping technique has resulted in transistors exhibiting breakdown voltages well in excess of the planar junction limit. Further extensions of the method predict LDMOSTs having active surface area less than or comparable to vertical MOS devices without sacrificing breakdown voltage or on-resistance.

Analysis and perfomance characteristics of an intensified silicon vidicon tube

Typical performance characteristics for intensified silicon vidicon tubes are given. The tube can be operated at 5 × 10-7_ fc faceplate illumination. A 40 percent modulation depth at 400 TV lines per raster height has been achieved at a 300-nA signal level. When operating at 200-nA signal, typical decay lag performance shows less than 20-nA signal 50 ms after the illumination is removed. Theoretical and experimental performance at low light levels are compared. The design of the electron optical system of the intensifier section is considered with respect to distortion and center and edge resolution. Two important target parameters, collection efficiency and resolution, are also considered theoretically and experimentally. A simple model for the collection efficiency is given; theory and experiment compare well. The effect on resolution of discrete diode spacing and target thickness is given and this is coupled with other modulation transfer parameters to predict the overall modulation transfer of the device. Critical performance characteristics are given for sample tubes.

Variable gain X-ray image intensifier tube

An X-ray image intensifier tube with a variable gain SIT (silicon intensified target) target has been developed. The X-ray SIT tube has a gain control range of 300 to 1, low noise, 1500 TVL/ diameter limiting resolution, and picture quality comparable to that obtained with optically coupled X-ray intensifier-vidicon combinations. The variable internal gain of the X-ray SIT tube makes it possible to produce an electronic radiographic imaging system that can be used for both low-exposure-rate fluoroscopic examinations and high-exposure-rate, short-duration fluorographic recordings. Design considerations for the X-ray SIT target are presented, and a detailed analysis of the target noise is given. The measured characteristics of 6- and 9-in input diameter X-ray SIT tubes are summarized.

Suppression of pedestal noise in a pyroelectric vidicon

A technique for suppressing pedestal noise and nonuniformities in a pyroelectric vidicon (PEV) is described. Demonstration of this method has been accomplished in a reduced frame rate/reduced line rate system. The minimum resolvable temperatures obtained with this noise-suppressed system are better by a factor of 3 to 4 than those obtained with a standard chop-mode PEV system.

Characteristics of pyroelectric vidicon with a reticulated target

Abstract Resolution of the pyroelectric vidicon (PEV) can be improved by reticulating the target. The TGS family can be reticulated by standard ion milling, but DTGFB material is difficult to ion mill under normal conditions. This paper discusses results with reactive ion milling techniques. Aspect ratios of 4:1 have been achieved in DTGFB with no inherent physical or chemical damage to the delicate pyroelectric material. Several PEV tubes with reticulated DTGS and DTGFB targets were built and tested. Tubes with reticulated DTGS show significant improvement in sensitivity and MTF whereas tubes with reticulated DTGFB showed modest improvements over tubes with conventional single crystal targets.

Matrix addressed electrophoretic displays

Electrophoretic image displays (EPID) exhibit excellent optical characteristics, good response times, and low power consumption. However, there is no readily accessible voltage threshold in the optical response for an EPID device, and hence standard x-y addressing techniques are not applicable. This paper will describe a practical and reliable technique for providing such a threshold based upon the use of a control electrode. The control electrode design permits x-y addressing at I.C. compatible voltages, line at a time addressing rates of approximately 5 msec per line and high resolution (5 lines/mm). The design and fabrication of prototype 7×9 matrix alphanumeric devices will be described and preliminary performance characteristics will be presented.

An electrophoretic X-ray imaging device

A new, self-contained, potentially very large-area electrophoretic X-ray-sensitive imaging device has been developed. This device can be set, developed, and erased by simply applying the proper potentials to the electrodes. The device has been realized in both a diode and triode electrode configuration. In the diode structure full black-to-white contrast has been achieved with 1-mR exposure and 4-lp/mm resolution.

TGFB and DTGFB pyroelectric vidicons

New pyroelectric vidicons (PEVs) have been developed employing targets of tri-glycine fluoroberyllate (TGFB) and deuterated triglycine fluoroberyllate (DTGFB). These tubes provide significant advances in the state-of-the-art of PEV performance. The best performance of PEVs previously reported was a panning-mode minimum resolvable temperature (MRT) of 1°C at 250 television lines/picture height (TVL/PH) with a pedestal current of 100 nA for tubes having triglycine sulfate (TGS) targets and non-crossover guns. Under the same conditions, the PEVs with these new target materials show an MRT of approximately 0.5°C at 250 TVL/PH.