摘要:

The electrical properties of m.i.s. structures based on indium phosphide and organic films deposited using the Langmuir-Blodgett technique have been investigated. A strongly inverted low-frequencyC/Vresponse occurs at approximately 30 Hz using both melt-grown InP single crystals and epitaxial layers of this material prepared using the vapour-phase technique. Interface state distributions have been evaluated from the admittance data using quasistatic and conductance techniques. For ann-type InP-epitaxial-wafer/cadmium-stearate junction the effective surface-state density is found to be ∼3 × 1011cm−2eV−1over a large fraction of the bandgap. Average surface-state densities calculated for structures based on melt-grown crystals were approximately one order of magnitude higher. For the first time measurements are reported for a transistor incorporating a Langmuir-Blodgett film. From the transfer characteristics of this relatively simple depletion-mode device the InP field-effect surface mobility is calculated to be 2250 cm2V−1s−1

DOI:10.1049/ij-ssed.1978.0053

出版商:IEE    

年代:1978

数据来源: IET

摘要:

The operating principles of the carrier-domain magnetometer are described. This novel semiconductor magnetic-field sensor produces output current pulses with a frequency proportional to the magnitude of the magnetic-flux density acting normally to the surface of the device. Experimental results are presented to demonstrate the sensitivity of the magnetometer. Anomalous features of device operation are explained; in particular, the existence of a threshold magnetic-flux density below which the device will not respond.

DOI:10.1049/ij-ssed.1978.0054

出版商:IEE    

年代:1978

数据来源: IET

摘要:

Mode-locked laser pulses of less than 10 ps duration are used to switch electrical gates made from microstrip line on high-resistivity silicon, in 10 ps. These gates can generate steps and pulses of around 100 V with 10 ps rise and fall times. Sampling can also be accomplished with a 10 ps aperture. By combining a group of such gates, along with the generation of appropriate laser pulses and timing signals, a sampling system is formed. Simple time-domain reflectometry measurements are made to demonstrate the system and to show that practical transitions to these gates can be made for signals at least up to 35 GHz.

DOI:10.1049/ij-ssed.1978.0055

出版商:IEE    

年代:1978

数据来源: IET

摘要:

Due to impurity redistribution and ion implantation, m.o.s. transistors are usually doped nonuniformly beneath the gate. From an analytical solution of Poisson's equation a modified expression for the threshold voltage has been derived. The change in the impurity concentration is taken into account, on the one side, in the usual manner by its contribution to the surface charge and, on the other side, on the basis of its contribution to the surface potential instead of the rather arbitrary approximation by an ‘effective’ impurity concentration. The modified formula gives a better description of the measured threshold voltages at least for an extended region, if not for the entire range of the applied substrate bias voltage. As theoretically predicted, the substrate bias coefficient corresponds to the bulk impurity concentration. A comparison with experimental results shows exceptionally close agreement if the depletion layer fully, or largely, covers the region of altered impurity concentration. If this region extends substantially beyond the depletion layer, deviations are observed. This result has been confirmed from impurity profiles determined for the purpose of verification.

DOI:10.1049/ij-ssed.1978.0056

出版商:IEE    

年代:1978

数据来源: IET

摘要:

By operating a c.c.d. delay line in integration mode, that is stopping the transfer process for a relatively long integration time and then shifting the charge packets to the output, it is possible to make evident thermal generation processes known as ‘dark currents’. The first part of the paper describes in detail the generation processes that take place in the structure during the integration time, in the case of uniform bulk and surface generation parameters. An experimental technique based on this mode of operation is then presented: it is shown that it allows the easy separation of bulk and surface components of the dark currents. This technique also allows the precise localisation of small electrically active defects, and some experimental results, supported by X-ray observations, are presented.

DOI:10.1049/ij-ssed.1978.0057

出版商:IEE    

年代:1978

数据来源: IET

摘要:

A novel technique is described for linear sensing of charge in tapped charge-coupled devices. It uses two gates. One is biased by a voltage source and one is floating, but both are coupled by surface-potential equilibrium. It is shown, experimentally and theoretically, that this technique has better linearity and dynamic range than floating-gate sensing. It has the same ease of peripheral circuit implementation as a floating-gate structure.

DOI:10.1049/ij-ssed.1978.0058

出版商:IEE    

年代:1978

数据来源: IET

摘要:

An exploratory electronically programmable transversal filter suitable for analogue signal processing has been realised and successfully operated. The basic element of the system is an eight sample parallel-operated intracell charge-coupled device. Results obtained in optimising the drive parameters of pulse amplitude, width and time are presented and discussed in relation to device physics and operation. Autocorrelations of unipolar analogue and digital signals are presented. These devices are ideally suitable for incorporation in a system using digital storage of the weighting information. An advantage of introcell c.c.d.s with integrated on-chip control logic would be the ease with which such devices could be interconnected to provide any desired signal-processing capability. This would enable a flexible modular approach to be adopted when designing complex signal processors.

DOI:10.1049/ij-ssed.1978.0059

出版商:IEE    

年代:1978

数据来源: IET