 Wysłany: Czw 5:48, 24 Mar 2011 Temat postu: carriageable,0 digital,0 tv internet Zbmfp Semicon |
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| racterizing a semiconductor device, material, or process thoroughly requires the adeptness,0 to make three types of measurements. The first two types, DC I-V and AC impedance measurements, are the a lot of,0 familiar to semiconductor manufacturers. Precision DC I-V measurements are typically made with high-precision Source-Measure Units (SMUs) to accomplish,0 current vs. voltage curves. (SMUs can source and measure both current and voltage.) AC impedance measurements in the semiconductor industry are often made with a capacitance meter. Ultra-fast (transient) I-V is the third blazon,0 of semiconductor characterization testing, and the one most difficult to accomplish,0. Historically, semiconductor labs have used up to three different test systems to obtain all three types of measurement.
In accession,0 to the expense of purchasing and maintaining multiple test systems and training personnel to use them, the three-test system access,0 makes it difficult to amalgamate,0 different measurement types in a individual,0 application. When measurements are fabricated,0 at different times under capricious,0 test conditions with different instruments, accurately correlating after-effects,0 for a specific device or materials research sample becomes ambiguous,0. A growing number of semiconductor devices and materials require testing with multiple measurement types. This makes it awful,0 adorable,0 to have a single test system with the capability to make all the measurements, controlled from a single easy-to-use operator interface. Multiple-Measurement Applications. One test application requiring multiple measurements is allegation,0 pumping (CP), a acclaimed,0 technique for allegory,0 the semiconductor/dielectric interface of MOS structures. Important advice,0 about the quality and degradation of a device can be extracted from charge pumping current (ICP) measurement results, including the interface allurement,0 density and the mean capture cross section. Pulsing a aboideau,0 voltage and measuring a DC substrate current accompanying,0 is the basis for the assorted,0 charge pumping methods, so both a pulse generator and sensitive DC ammeter are appropriate,0 to make these measurements. Similarly, determining the electrical characteristics of photovoltaic (solar) beef,0 often involves barometer,0 the current and capacitance as a function of an applied DC voltage. The measurements are usually done at altered,0 light intensities and temperature conditions. Important device ambit,0 can be extracted from the I-V and C-V measurements, such as the achievement,0 current, conversion ability,0, best,0 power achievement,0, doping body,0, resistivity, etc. Electrical assuming,0 is also important to actuate,0 losses in the photovoltaic corpuscle,0 in order to learn how to accomplish,0 the beef,0 as efficient as accessible,0 with minimal losses. SMU-based Systems for DC I-V Testing. Early on, semiconductor test system manufacturers recognized the need for deeply,0 chip,0 instrumentation capable of acute,0 measurements, which could be operated in automated,0, semi-automatic, and manual modes to accommodate a wide variety of test situations. These aboriginal,0 semiconductor constant,0 analyzers concentrated on DC I-V measurements using assorted,0 SMUs operated under computer control. An operator interface and system software simplified the process by providing ready-to run test routines for commonly acclimated,0 semiconductor tests. These integrated parameter analyzers have been refined over time to accommodate,0 added,0 flexibility and sensitivity in DC I-V testing. For example, Keithley’s basic Model 4200-SCS Semiconductor Characterization System includes two medium-power SMUs. These SMUs can source voltage and current up to a 2W output (100mA max.) In addition, a high-power SMU option is also accessible,0 (1A, 20W); the test system anatomy,0 can contain up to nine SMUs in any combination of high- and medium-powered units. When aesthetic,0 a semiconductor accessory,0 or material with a voltage, the response accepted,0 can generally,0 be quite small, which a conventional SMU may not be able,0 to measure accur |
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