A figure of merit for IC packaging

Powering integrated circuits is a compromise between increasing power to increase circuit speed and maintaining high packaging density while satisfying cooling constraints. The optimization of this compromise provides the basis for a packaging figure of merit.     

A figure of merit for a varactor-tuned microwave oscillator

This note derives a figure of merit for a varactor tuned microwave solid state oscillator. Thu figure of merit is in terms of electronic tuning range and power output normalized to the available power from the untuned oscillator. This enables the varactor which will give the required combination of thorns parameters to be specified in terms of y and f _c.

The figure of merit also shows that a varactor with a large value of the product yf _c maximizes the figure of merit.     

A figure of merit for signal processing reflector antennas

In recent years a new class of reflector antennas utilizing array feeds has been receiving attention. An example of this type of antenna is a reflector utilizing a moveable array feed for beam steering. Due to the circuitry required to adjust the weights for the various feed array elements, an appreciable amount of loss can be introduced into the antenna system. One technique to overcome this possible deficiency is to place low noise amplifiers with sufficient gain to overcome the weighting function losses just after each of the feed elements. In the evaluation of signal processing antennas that employ amplifiers the standard antenna gain measurement will not be indicative of the antenna system's performance. In fact, by making only a signal measurement, the antenna gain can be made any arbitrary value by changing the gains of the amplifiers used. In addition, the IEEE Standard Test Procedures for Antennas does not cover the class of antennas where the amplifier becomes part of the antenna system. There exists a need to establish a standard of merit or worth for multi-element antenna systems that involve the use of amplifiers. A proposed figure of merit for evaluating such antenna systems is presented.     

A figure of merit for the high-frequency noise behavior of bipolartransistors

In this paper a new figure of merit for high frequency noise behavior for use in the evaluation and development of bipolar silicon process technology is introduced. Basic low noise design rules for optimum transistor biasing and emitter scaling are proposed     

Power semiconductor device figure of merit for high-frequencyapplications

A figure of merit (the Baliga high-frequency figure of merit) is derived for power semiconductor devices operating in high-frequency circuits. Using this figure of merit, it is predicted that the power losses incurred in the power device will increase as the square root of the operating frequency and approximately in proportion to the output power. By relating the device power dissipation to the intrinsic material parameters, it is shown that the power loss can be reduced by using semiconductors with larger mobility and critical electric field for breakdown. Examination of data in the literature indicates that significant performance improvement can be achieved by replacing silicon with gallium arsenide, silicon carbide, or semiconducting diamond     

A standby current limited performance figure of merit for deepsub-micron CMOS

The delay time of an inverter or NAND chain at a gate length yielding equal standby current and active current is used as the definition of a maximum Figure of Merit (FOM), FOM_max. The circuit power that occurs under this condition of equal standby and active currents is an equally important measure. This FOM_max technique is particularly useful in characterizing complementary metal-oxide-semiconductor (CMOS) technologies in the deep submicron regime. A knowledge of the exact value of gate length is not necessary to apply the FOM_max methodology. For a fixed supply voltage and gate oxide thickness, node capacitance and transistor drive, and off currents determine the value of FOM_max. The value of gate length at which FOM_max occurs decreases with decreasing supply voltage. FOM_max analysis is applied to the comparison of CMOS technologies using gate oxide thicknesses of 5.7 and 3.8 nm     

A simple figure of merit for evaluating interleaver depth for theland-mobile satellite channel

The selection of interleaver depth for the land-mobile satellite channel is investigated by analyzing the performance of convolutionally encoded BPSK and DPSK over a frequency-nonselective correlated Ricean fading channel. By extending previous analyses of partially interleaved convolutional codes over such channels, a new figure of merit-which is a function of the channel correlation function-is identified. Simulation results for the first-order Butterworth, Jakes (1974), and Divsalar (1991) fading spectra are presented which demonstrate the applicability of the figure of merit as an aid in interleaver design. The figure of merit also tracks the nonmonotonic, or quasi-oscillatory, behavior of the decoded bit error rate with increasing interleaver depths in those situations where this occurs     

An appropriate device figure of merit for bipolar CML

The effects of base resistance, base transit time, and junction capacitances play a key role in the propagation delay of high-speed bipolar logic gates. A simple device figure of merit for transistors used in current mode logic (CML) circuits, based on minimum propagation delay, is developed. This delay is derived from the large-signal 3-dB cutoff frequency of the CML gate. Results are shown to be applicable for a wide range of device and circuit parameters     

Improved figure of merit for noise in avalanche photodiodes

The authors propose a new noise figure for avalanche photodiodes (APDs). This new noise figure overcomes the difficulty of estimating the internal multiplication and quantum efficiency in complex APD structures, such as III-V SAM APDs. Measurements of the new noise figure are presented for two commercial SAM APDs and the authors show theoretically that it represents a more complete figure of merit for comparing the performance of one APD with another, and with the ideal     

Thermoelectric figure of merit of LSCoO-Mn perovskites

Oxide ceramics with nominal composition of were grown by using the citrate sol-gel method followed by high temperature sintering. The thermoelectric properties were studied in the temperature range between 100 and 290 K. The magnitude of Seebeck coefficient S(T) and electrical resistivity ρ(T) increases with the manganese doping level, reaching maximum values close to and , respectively. On the contrary, the total thermal conductivity κ(T) decreases with the manganese content. The behavior of S(T) and ρ(T) was interpreted in terms of small-pollaron hopping mechanism. From S(T), ρ(T) and κ(T) data it was possible to calculate the dimensionless thermoelectric figure of merit ZT, which reaches maximum values close to 0.12; the structural and morphological properties of the samples were studied by powder X-ray diffraction analysis and scanning microscopy (SEM), respectively.     

Thermoelectric figure of merit of a p-n junction

The thermoelectric figure of merit of a semiconductor p-n junction is calculated in terms of the diode theory taking account of the bipolar thermal conductivity. The thermoelectric figure of merit of a Bi₂Te₃ diode is estimated and it is shown that the Ioffe criterion may be at the same level as the best modern thermoelectric materials but cannot exceed unity.     

Thermoelectric figure of merit for bulk nanostructured composites with distributed parameters

The effective properties of composites whose structure includes nanocontacts between bulk-phase macrocrystallites are considered. A model for such a nanostructured composite is constructed. Effective values of the thermoelectric power, thermal and electrical conductivities, and thermoelectric figure of merit are calculated in the mean-field approximation.     

Comparative logic figure of merit of current high-speed transistors

A CCD split-electrode transversal filter (EPSEF) with analog controlled tap weights is described. The programmable tap weighting utilizes a novel analog multiplier for sampled data, based on charge profiling underneath a resistive gate structure. The EPSEF device concept and the performance data of a prototype filter with eight programmable taps are presented. Applications of the EPSEF in several programmed filter functions and in an adaptive filter system are demonstrated.     

Synthesis of base impurity distributions for improved figure of merit of transistors

This paper deals with the problem of determining the impurity distribution which will improve the minority carrier base transit time and figure of merit of transistors. From the study of a special form of doping distribution which presents a point of inflection in the resulting built-in electric field configuration, it is concluded that the optimum doping distributions derived through variational methods [2–4] do not necessarily offer a unique minimum for base transit time. A new technique called “The Segmentation Technique” is evolved to synthesise base impurity distributions for improved high frequency performance of present-day junction transistors. It is shown that typical impurity distributions presenting retarding field over a small portion of the base and an aiding field over the rest of the base region offer a significant improvement in base transit time and the high frequency figure of merit.     

Gain-sensitivity product-a figure of merit for hybrid-integrated filters using single operational amplifiers

It is shown that a different measure of performance must be used to evaluate hybrid-integrated active filters from that used to evaluate active filters in discrete form. Where sensitivity was previously found to be an adequate and useful measure for Q stability of discrete active filters, the gain-sensitivity product gives an accurate measure of Q stability for hybrid-integrated circuits. Where negative feedback filter schemes were found to be preferable with respect to Q stability when realized in discrete form, positive feedback schemes with their very much lower gain- sensitivity product may be preferable in hybrid-integrated filter circuits. In addition, they require low-gain amplifiers than can be used up to higher frequencies. Q-stability measurements of hybrid- integrated positive feedback, or Sallen-Key-type circuits, which were realized with tantalum thin-film resistors and capacitors combined with beam-leaded operational amplifier chips agree very accurately with the predictions derived from gain-sensitivity calculations.     

关于微光像增强器的品质因数

20世纪60年代以来,微光夜视像增强器的技术进步一直是以“代”来评价的。通常理解是一代比一代优越。20世纪,在微光夜视像增强器发展的过程中,相继出现60年代的纤维光学面板级联耦合的像增强器(第一代),70年代的微通道板像增强器(第二代)和80年代的GaAs负电子亲和势光阴极像增强器(第三代)。从事夜视技术的科学家们一直在探索新一代或第四代像增强器技术。什么是第四代,在夜视学术界是有争论的。问题在于,像增强器以代来划分,以代来评价,是否合适和全面;评价像增强器的优劣是性能还是技术;以什么表示像增强器的性能更好和更全面;这些问题引起了夜视学术界的深思。文中阐述了微光像增强器总体性能应以品质因数而不是代的概念进行评价。     

Thermoelectric figure of merit of monopolar semiconductors with finite dimensions

The figure of merit of monopolar nondegenerate semiconductors is theoretically investigated. The difference between the electron and phonon temperatures, which arises as a result of the action of different surface mechanisms of energy relaxation at the contacts of the sample with the heat reservoir, is taken into account. It is shown in the case of isothermal boundary conditions for the electron subsystem and adiabatic conditions for the phonon subsystem that the thermoelectric figure of merit of the sample increases with decreasing sample’s linear dimensions and reaches its maximum in films of submicron thickness. Fiz. Tekh. Poluprovodn. 31, 323–325 (March 1997)