M. Jamal Deen

Low frequency noise in polysilicon‐emitter bipolar junction transistors

This paper describes experimental results on low frequency noise in several types of polysilicon‐emitter NPN bipolar junction transistors. The experimental data were modelled using a combination of 1/f noise, generation‐recombination noise (g‐r), and shot noise, and good agreement between model calculations and experimental measurements were obtained. Observed differences in the experimental low frequency noise spectra of devices with similar geometry and under similar biasing conditions could be explained by the differences in the generation‐recombination (g‐r) noise contributions. Experiments were performed on devices with emitter areas varying from 1.6 to 144 μm2, and it was found that the magnitude of the flicker noise contribution KF varied inversely with emitter area AE or emitter perimeter PE. The fact that KF∼A−1E or KF∼P−1E is explained by the observation that AE∼PE within fabrication errors/tolerances. Using a set of 3.2 μm2 BJTs with pronounced g‐r noise, input current noise was measured at dif...

Measurements and comparison of low frequency noise in npn and pnp polysilicon emitter bipolar junction transistors

Low frequency noise characteristics of new high voltage, high performance complementary polysilicon emitter bipolar transistors have been studied. The influence of the base biasing resistance, emitter geometry, and temperature on the noise spectra are discussed. The npn transistors studied exhibited 1/ f and shot noise. The pnp transistors, on the other hand, are characterized by significant generation-recombination noise contributions to the total noise. For both types of transistors, the measured output noise is determined primarily by the noise sources in the polysilicon‐monosilicon interface. The level of the 1/f noise is proportional to the square of the base current ( I B ) for both npn and pnp transistors. The contribution of the 1/ f noise in the collector current is also estimated. The magnitude of the 1/ f noise normalized to the square of the base current for devices with different emitter areas was found to be inversely proportional to the emitter area, but for the transistors with a large ratio of emitter perimeter to emitter area, the contribution of noise sources located in the emitter perimeter may be significant. For both pnp and npn transistors, 1/ f noise was found to be independent of temperature, and for pnp transistors, generation-recombination noise decreases with increasing temperature.

ON THE ORIGIN OF 1/F NOISE IN POLYSILICON EMITTER BIPOLAR TRANSISTORS

Low frequency noise in polysilicon emitter bipolar transistors (BJT) with different emitter areas (AE) was studied. In BJTs with submicron emitter area, random telegraph signals of different amplitudes and frequencies were found. Averaging of noise spectra from different submicron BJTs gives 1/f noise of the same level (normalized to the emitter area) as 1/f noise found in transistors with large emitter areas. The sheet density of traps (NT) located within the polysilicon–crystalline silicon interfacial layer and responsible for 1/f noise was estimated to be ⩾3×108u2009cm−2.

Generation-recombination noise in MOSFETs

A new analytical approach to the low frequency noise analysis in MOSFETs has been developed. Local levels contributing to generation-recombination noise are classified into three groups. For deep levels located near the midgap the approach of zero free carrier concentration inside the space charge region can be used. Simple analytical expressions and conditions of their applicability are derived. Parameters of levels located near the conduction and valence bands can be determined analytically. Analytical expressions for such a situation are also derived. For the intermediate case the level parameters can be only determined numerically. The low frequency noise in n- and p-MOSFETs has been studied experimentally at 220 K < T < 425 K over frequency range 2 Hz < f < Hz. Experimental noise spectra are analysed on the basis of developed theoretical model.

Effects of space-radiation damage and temperature on CCD noise for the Lyman FUSE mission

Charge coupled device (CCD) imaging arrays are becoming more frequently used in space vehicles and equipment, especially space-based astronomical telescopes. It is important to understand the effects of radiation on a CCD so that its performance degradation during mission lifetime can be predicted, and so that methods to prevent unacceptable performance degradation can be found. Much recent work by various groups has focused on the problems surrounding the loss of charge transfer efficiency and the increase in dark current and dark current spikes in CCDs. The use of a CCD as the fine error sensor in the Lyman Far Ultraviolet Spectroscopic Explorer (FUSE) is limited by its noise performance. In this work we attempt to understand some of the factors surrounding the noise degradation due to radiation in a space environment. Later, we demonstrate how low frequency noise can be used as a characterization tool for studying proton radiation damage in CCDs.

Organic Semiconductor Devices

In the past few decades, the applications of organic or polymeric semiconductors in photonics, electronics and optoelectronics have advanced significantly. This has been primarily because of improvements in the quality organic/polymeric materials after processing, as well as the processing techniques and technologies. For example, roll-to-roll, sheet-to-sheet or printing technologies are being proposed as suitable manufacturing candidates because they can be carried out at room temperature, do not require the kind of clean room environment needed for traditional semiconductor manufacturing, and are very suitable for very low-cost, high volume production. In this article, we concentrated on four types of organic semiconductor devices. Because of their huge commercial potential, a significant part of the article is devoted to light-emitting diodes (LEDs) made either with polymers or organic semiconductor materials. To improve the linewidth and enhance the efficiency of the LEDs, microcavities are discussed And for active display driver transistors and other electronic applications, thin-film transistors with organic semiconductors and all-organic transistors are described. Finally, photovoltaic cells, photodiodes, and metal–organic semiconductor junctions are discussed. n n n nKeywords: n nOrganic semiconductors; npolymeric semiconductors; nlight-emitting diodes (LEDs); norganic LEDs; npolymeric LEDS; nmicrocavities; norganic thin film transistors (OTFTs); npolymer TFTs; norganic photovoltaic; norganic solar cells; norganic photodiodes; nmetal–organic semiconductor junctions

Ionization coefficient measurements in InP by using multiplication noise characteristics of InP/InGaAs separate absorption, grading, charge, and multiplication (SAGCM) avalanche photodiodes (APDs)

Multiplied shot nose and gain-voltage characteristics of separate absorption, grading, charge and multiplication avalanche photodiodes were measured at 25 degrees C in a gain range of 3 to 30. Low optical input powers and a small spot size were used in order to minimize gain saturation effects and gain non-uniformity within the spot. The InP multiplication layer thickness and charge sheet density were extracted from capacitance - voltage characteristics and confirmed by SIMS. Electron and hole impact ionization coefficients in InP were then extracted using gain-voltage characteristics and McIntyres expressions. Possible deep level traps within the InP multiplication layer were characterized using temperature and frequency characteristics of capacitance - voltage measurements. Peripheral and active area capacitances were separated by studying devices with different active area diameters.

Design and simulated performance of a CARS spectrometer for dynamic temperature measurements using electronic heterodyning.

A new design for generating CARS signals and for the detection and processing of these signals is presented and evaluated. The design is based on electronic heterodyning of the CARS spectrum of nitrogen at two selected narrowband frequencies, ratioing the resulting signal strengths, and comparing this ratio with a theoretically derived temperature scale. A reference cell is incorporated into the design for system calibration and for accurate temperature measurements. The spectrometer is found capable of measuring temperature in the submillisecond time scale with an accuracy of 10% in the 1000-2000 K temperature range. A typical result using the Hg(x)Cd(1-x) Te photomixer for T = 1500 K,DeltaT = 50 K is a SNR of 21 dB and a data collection rate of 300 Hz.

Low frequency noise in npn and pnp polysilicon emitter bipolar junction transistors

Low frequency noise characteristics of a high voltage, high performance complementary polysilicon emitter (PE) bipolar transistors are described. The influence of the base biasing resistance, emitter geometry, and temperature on the noise spectra are discussed. The npn transistors studied exhibited 1/f and shot noise, but the pnp transistors, are characterized by significant generation-recombination noise contributions to the total noise. For both types of transistors, the measured output noise is determined primarily by the noise sources in the polysilicon-monosilicon interface. The level of the 1/f noise is proportional to the square of the base current both for npn and pnp transistors. The contribution of the 1/f noise in the collector current is also estimated. The area dependence of 1/f noise in both types of transistors, as well as other npn bipolar transistors are presented. Low frequency noise in a low voltage (5V and 10V), high performance npn transistor technology are also presented. For these t...

Some issues in high frequency noise modeling of MOSFETs

This paper presents two of the important issues in high frequency noise modeling of MOSFETs—the determination of the channel thermal noise and the removal of the pad effects. First, an extraction method to obtain the channel thermal noise in MOSFETs directly from d.c., scattering (s-) and noise parameters measurements is discussed. In this method, the transistor’s transconductance (gm), output resistance (RDS) and source and drain resistances (RS and RD) can be extracted from d.c. measurements. Its gate resistance (RG) is extracted from s-parameter measurements, and the equivalent noise resistance (Rg) is obtained from RF noise measurements at low frequencies. With these quantities known, the channel thermal noise can then be directly calculated. Second, for short-channel length MOSFETs, the effects of the pads can significantly distort the transistor’s noise parameters. Ideas on how this can be removed by appropriate experiments are described. Appropriate test structures for removing the effects of the p...