Thin Capacitors Research Articles

Effect of Electric Fields on the Absorption Spectrum of Dye Molecules in Lipid Layers. IV.) Electrochromism of Oriented Chlorophyll b

AbstractThe spectra of the linear and the quadratic electrochromism of asymmetrically oriented chlorophyll b molecules are measured in thin capacitors. The linear electrochromism can be described mainly by shifts of the blue and the red absorption band in the electrical field.The quadratic electrochromism can be described mainly by a broadening of the blue and a shift of the red absorption band. According to theoretical considerations of a foregoing paper [1], the mean components in the direction of the field for the dipole moment differences between the ground state and the excited states of the blue and the red absorption band can be calculated, by comparing the electrochromic spectra with the first and second derivative of the absorption spectrum. The polarizability difference for the red absorption band is also obtained in this way.The linear electrochromism around 480 nm agrees well with a light‐induced absorption‐change of a chloroplast suspension at this wave length [5]. From the comparison, valuable conclusions concerning the light‐induced electric field and the asymmetrical distribution of the molecules in the biological membrane can be drawn: The porphyrin rings of the chlorophyll b molecules must be oriented with the corner bearing the phytol chain towards inside of the thylacoid and must be subdued after a short single flash to a light‐induced electric field of about 105 V/cm. This agrees well with other calculations [16].

Electrochromic Spectra of Dyes in Lipid Layers

AbstractK.‐U. SeweIn order to provide a basis for the identification and analysis of electrochromic absorption‐changes of dyes in biological membranes, electrochromic spectra of dyes in thin capacitors are measured and discussed theoretically in terms of a foregoing paper [1].

Automatic Impedance Measurements Using Thermal Noise Analysis

An apparatus permitting measurements of current and voltage thermal noise of two terminal devices has been built using a correlator amplifier and a controlled amplitude white noise generator. It allows accurate determinations of device impedance components, especially of nonlinear devices such as thin ferroelectric capacitors.

Properties and Life Performance of Silicon Monoxide Capacitors

In SiO capacitors, deposition rate and thickness interact in their effect on leakage resistance. Slow (2 Å/s) and fast (20 Å/s) deposited films in the 2000-Å thickness range exhibit almost a million-fold difference in leakage, while similar rates, for 10000-Å films, show only a thousand-fold difference. Dissipation factor and temperature coefficient of capacitance (TCC), under the same conditions, also show extreme variation: dissipation factor from 0.003 (slow films) to 0.075 (fast, thin films), and TCC from < 40 ppm/°C (slow films) to 5700 ppm/°C (fast, thin films). Life tests of SiO capacitors were conducted at 85°C for periods up to 14 000 hours. They included capacitors with a thick (about 10 000 Å) dielectric layer and ones with a thin (about 1000 Å) layer. The thicker ones were under a potential of 47 volts dc and the thinner ones 10 volts dc. In addition, a small group of thick capacitors were held at 125°C, 67 volts dc for a much shorter time, about 6000 hours. The test results for thick 85°C capacitors were that no permanent dielectric failures occurred during the test period and dielectric properties were unchanged from those at the start of the test. Among the 60 thin capacitors, four failures (on the same substrate) occurred during the final tenth of the life test period. Visual inspection indicated that aluminum electrode corrosion was responsible. Ten capacitors maintained at 125°C (only three under voltage stress) were in perfect condition at the conclusion of the test. Their capacitance had not changed significantly but the dissipation factor improved from 0.0075 to 0.0034 (average value of ten capacitors). The most significant finding regarding long-term instability is that aluminum electrodes often deteriorate, sometimes causing dielectric failure.

814. The manufacture of thin layer capacitors by means of electron beam evaporation: C.V. Planer, Vacuum Technik, 13 (4), May 1964, 116

814. The manufacture of thin layer capacitors by means of electron beam evaporation: C.V. Planer, Vacuum Technik, 13 (4), May 1964, 116

A system of tantalum film microcircuitry

INTFtODUCTION THE Bell Telephone Laboratories numbers itself among those organizations who are pioneering in new approaches to components and their assembly. We, as others, face the problem of implementing new complex electronic systems which will require very large numbers of components and interconnexions. Our motivation toward microminiaturization may differ in detail from that of some of our colleagues. Notably, the micro or miniaturization aspects are not to us the most important considerations. In some of our areas small size is important for itself but for most applications we consider it a fringe benefit. Our first concern is for economy, reliability and early practical application. The work to be described here has as its objective a process for the fabrication of groups of thin film resistors and capacitors of high electrical quality, and interconnexions, using as a basis a pattern of tantalum on an inorganic substrate. Fig. 1 illustrates such a circuit. This is the passive component complement for a three-stage flip-flop. It contains twenty-three resistors and nine capacitors. Metallized holes serve as sockets for transistors and diodes.