High-speed Diode Research Articles

An Inexpensive Fast-Light Detector for Student Laboratories

A high-speed PIN diode and a transistor amplifier have been evaluated for use in student experiments with a pulsed-ruby laser. The electrical transient response of the amplifier and cabling was determined with a 1-nsec TDR pulse. The optical response of the entire system was checked with light pulses produced by reflecting a He-Ne laser beam onto the detector with a high speed rotating mirror. Pulses with 36-nsec risetimes were clearly resolved.

Filters for High-Speed Diode Modulators and Demodulators

The relationship between switching time, transient suppression, and filter complexity is derived for filter-type diode switches, along with the theoretical minimum switching time. Design criteria are developed for high-speed switches and detectors in waveguide and TEM transmission lines.

High-speed photodiode signal enhancement at avalanche breakdown voltage

It has previously been found that when photons are injected into a photodiode biased to the avalanche region, that there is a multiplication of the signal over the usual bias-voltage signal level. This multiplication is due to the created electron-hole pairs colliding with the lattice and creating more electron-hole pairs under the influence of the large biasing field. This paper presents a circuit analysis of this effect when using a high-speed silicon (Si) P-I-N photodiode and shows what the SNR bandwidth and Noise Equivalent Power (NEP) are under both normal bias conditions and avalanche bias conditions. It is shown that there is a substantial improvement in the NEP and SNR ratio at high frequencies when operating at avalanche so that the device may be made nearly shot noise limited if the multiplication factor <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">M</tex> is sufficiently large. Microwave measurements on such a high-speed diode gave gains greater than 30 dB with a SNR improvement of 13 dB at 1.45 Gc/s. The effect was observed at frequencies as high as 2.54 Gc/s and appeared to follow a linear 1/M law with bias voltage in the avalanche region with some deviation at large values of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">M</tex> . The device SNR ratio at moderately high light levels is determined by the signal-to-shot noise ratio. A high modulation depth is found to be essential to reduce shot noise. Analysis of the diode circuit reveals that the detected signal power bandwidth product is a constant. The NEP is found to vary directly with the bandwidth in a pulse type system. Avalanche operation increases the signal power by M <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and decreases the NEP by <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">M</tex> at high frequencies. The photodiode appears to nearly provide the solid-state analog of the photomultiplier tube.

A 600-kV, 10-mA DC Cockcroft-Walton Rectifier Using Silicon Diodes at 100 kc

In this rectifier high-speed silicon diodes, etched circuit boards, and SF6 are combined in a style of construction that requires only the modest shop facilities of any typical small physics laboratory. This paper covers construction techniques, performance tests, electronic regulation, high-speed protection circuitry, and application of the rectifier to experimental equipment. The technique described can be extended to larger sizes providing several million volts.

A High-speed tunnel diode counter

The tunnel diode binary counter circuit reported by Kaenel and subsequently discussed by many authors is described. The mode of operation of the circuit is explained in terms of a piece-wise linear model for the tunnel diode. The switching trajectories obtained using a low frequency analogue simulation of the circuit are used to discuss the bias and trigger conditions to be employed. A method of intercoup

A Method of Theoretical Analysis of High-Speed Junction Diode Logic Circuits

The charge storage (and, consequently, the recovery time) problem of a p-n junction diode has been a most troublesome phenomenon in the application of junction diodes in switching circuits. If many diodes in a logic gate are switched simultaneously from conduction to cutoff, large sums of stored charge will be generated and will tend to reverse the state of the nonswitching diodes in the same circuit. Accordingly, a possible false logic response may result. Unfortunately, the diode models presently available are useless for analyzing such transients. For this reason, a new diode model has been devised. From a study of the physical process in a junction diode, a unique relationship can be established between the terminal electric properties and the charge storage in the base material, of the diode. The relationship can be shown in a simple flowgraph. From this flowgraph a lumped charge model of a p-n junction diode is proposed. Utilizing this model, one can simply and uniquely solve the transient problems encountered in diode switching circuits, while only two parameters, the saturation current I <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</inf> , and the diode time constant T <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d</sup> , are required to evaluate the solution numerically.

A method of i.f. switching for a microwave diversity system

This paper deals with the various factors involved when considering the use of diversity on a microwave radio link. Various systems of if. switching are briefly surveyed. An i.f. switching circuit designed for use on such systems is described which uses high speed diode switches working at the i.f. of 70 Mc/s. The switch control circuits are partially transistorized.

Fabrication of a rugged, low-peak current high-speed tunnel diode

A major problem of high-speed tunnel diodes has been poor reliability due to fragility of the very small area junctions needed for low capacitance. This paper describes a solution to the problem, based upon building a mechanical support very close to the junction. Important factors in the selection of the geometry of the supporting structure are discussed. Two general fabrication methods are presented and compared. Electrical and mechanical characteristics and short-term reliability test results are given for diodes made by the processes described.

The design and performance of a high-speed silicon diode

With the increasing use of high-speed switching techniques a need has arisen for diodes with a fast transient response. The paper first considers the various methods by which the speed of semiconductor diodes may be improved by reducing carrier storage. In the silicon device described, this is accomplished by a reduction of the lifetime of the basic material. Of the two methods investigated, neutron bombardment and heat treatment, the latter was found to be the more effective. The heat treatment involves quenching the silicon from a temperature in excess of 1000°C. The paper then discusses the effect on the static characteristics of diodes made from silicon quenched in this manner. As a consequence of the reduction in lifetime the conductivity modulation of the base region is decreased, resulting in an inferior forward characteristic. In general, the reverse currents and breakdown voltages found are somewhat higher than in devices made with untreated material. A typical diode fabricated from silicon quenched from 1150°C passes a forward current of 10 mA at 1 volt, and has a reverse current of 0.1 ?A at ?100 volts. The methods of measuring the transient response of the device are discussed, and a comparison is made between them. A typical device has a switching time less than 0.2 microsec and a total recovered charge of 10?10 coulomb.

High-Speed Switching Diodes from Plastically Deformed Germanium

Diffused diodes, fabricated from plastically deformed germanium, were examined for high-speed switching response. The degradation of minority carrier lifetime caused by dislocations generated during plastic deformation greatly reduced the minority carrier storage effect and permitted fabrication of diodes with turnoff times of the order of 10−9 sec.