RU2799113C1 - Method for increasing speed of transistors and transistor integrated circuits - Google Patents

Abstract

FIELD: electronics; microelectronics.

SUBSTANCE: method for controlling the speed of transistors and transistor integrated circuits includes exposing the semiconductor structures of transistors and transistor integrated circuits to a photon flux from an LED or a low-power laser, while transistors, transistor integrated circuits, an LED or a low-power laser are placed in one housing, and affecting the semiconductor structures of transistors and transistor integrated circuits are carried out by a continuous stream of photons from an LED or a low-power laser during the operation of transistors and transistor integrated circuits.

EFFECT: increasing the speed of semiconductor devices and integrated circuits.

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Description

The invention relates to the field of electronics and microelectronics, namely to the operation of discrete bipolar and field-effect transistors, as well as integrated circuits based on bipolar and field-effect transistors.

Increasing the performance of peripheral digital devices is possible with the use of instruments and principles of optoelectronics. The following optoelectronic devices are known from the prior art:

1. Electronics. Encyclopedic Dictionary. Ch. ed. V.G. Kolesnikov. – M.: Sov. Encyclopedia, 1991. - S. 348-351.

2. Nosov Yu.R. Optoelectronics. - M.: Radio and communication, 1989. - 360 p.

3. Rozensher E., Winter B. Optoelectronics. - M.: Technosfera, 2004. - 592 p.

4. Till U., Lakson J. Integrated circuits. Materials, devices, manufacturing. - M.: Mir, 1985. - 504 p.

The phototransistor and photothyristor are devices that use illumination of semiconductor layers instead of control electrodes. The optothyristor differs in that the light source - a GaAs LED - is built into a common housing with a silicon thyristor structure. In practice, optocouplers are widely used, which consist of an emitter and a photodetector in a single package. As a rule, an LED is used as an emitter. Photodetectors are photoresistors, photodiodes, bipolar and field-effect phototransistors, photothyristors. The principle of operation of most optoelectronic devices is to convert light signals into electrical signals in the absence of galvanic isolation in the control circuit. This is due to the internal photoelectric effect - when a semiconductor structure is illuminated, electron-hole pairs are generated in it and a control photocurrent is created.

There are various technical solutions for optoelectronic integrated circuits. Some of them are described in JP 2007096305 A, US 9202971 B2, US 2018/0040597 A1, US 2018/0323873 A1. Such integrated circuits are receivers or transmitters of optical signals that can be used, for example, in fiber optic communication lines (FOCL).

US 2018/0372781 A1 proposes voltage and current sensors using an optical coupled isolator.

According to their functions, optocouplers can replace transformers.

An optically coupled isolator can be used as a power gate to reduce power consumption. Power savings are achieved by selecting phototransistors and adjustable bias resistors to set the minimum photodiode forward current and reduce battery drain while still providing sufficient gain for the optical transistor. The bias voltage can be chosen to be equal to the turn-on voltage of the photodiode. In addition, the power consumption of the voltage and current sensors can be adjusted by adjusting the frequency of the control signal using a microcontroller.

A common disadvantage of the available optoelectronic devices and integrated circuits is the impossibility of their use as logic elements for creating integrated circuits of digital devices and microprocessors with a high packing density.

The task of increasing performance is extremely relevant for digital devices and microprocessors. Known methods for increasing the speed of semiconductor devices and integrated circuits are mainly divided into two types: constructive-technological and circuitry. Structural and technological methods include miniaturization of active and passive components on a chip, reduction of parasitic capacitances, operation in modes with high base and collector current densities or drain current, and reduction of voltage drops between low and high levels in signals. Circuitry methods allow for the same technological structure of the chip to achieve high-speed operation by implementing certain circuit solutions. Here, forcing the dynamic mode with the help of corrective circuits, the use of clamping and shunt diodes, non-linear feedback and current switches are highlighted.

The objective of the present invention is to apply the principles of optoelectronics to increase the speed of transistors and integrated circuits based on them.

The main difference of the proposed method for increasing the performance from the known technical solutions in optoelectronics is the absence of physical and design restrictions associated with galvanic isolation in control circuits. The traditional structure of bipolar and field-effect transistors with base and gate electrodes is preserved.

The essence of the invention is as follows. On the surface of a semiconductor crystal of a transistor or an integrated circuit during its operation, a stationary and continuous photon flux falls from the emitter (Figure 1). The intensity of this flow can be precisely controlled by an external device. In a thin near-surface layer of the crystal, nonequilibrium electron-hole pairs are generated, and the currents of the majority and minor charge carriers increase in the active regions of the device structures. In relation to a bipolar transistor, this leads to a decrease in the opening voltage (less than 0.6 V for silicon, less than 0.3 V for germanium), an increase in the base current transfer coefficient in a circuit with a common emitter, which depends on the efficiency of the emitter, an acceleration of the transfer of minor charge carriers in the base, and a decrease in surface recombination [p.184]. In field-effect transistors MOS and with a control pn-junction, continuous irradiation with photons reduces the threshold voltage [p.217] and cutoff voltage [p.250], and also increases the currents of the main charge carriers in the channels. When exposed to a photon flux on bipolar or field integrated circuits, their static and dynamic characteristics change. Reducing the opening or cutoff voltages of transistors leads to a decrease in the threshold voltages of logic elements and gates in the integrated circuit, a narrowing of the switching range between low and high signal levels, and a decrease in power consumption. In addition, the continuous exposure to a stream of photons makes transistors and integrated circuits insensitive to external radiation exposure. Thus, the problem of radiation resistance is solved in passing. In general, it can be said that the external emitter creates a kind of optical pumping for semiconductor devices and integrated circuits. [4]

In FIG. Figures 2-4 show examples of the results of a study of the static and dynamic characteristics of a switch on a discrete bipolar npn transistor in a single package with an emitter in the form of a "white" SMD LED. On all graphs, characteristics (a) and (b) were measured, respectively, with the emitter turned off and on. It can be seen that the action of the emitter leads to an effective decrease in the switching threshold, an increase in the output current, and a noticeable decrease in the average switch delay time. In FIG. 5 for two different bipolar npn transistors shows the dependences of the base current transfer coefficient in a common emitter circuit on the product of current and voltage in the control circuit, that is, in fact, on the electrical power consumption of the SMD LED. Linear dependencies are found here. It can be seen that by using an LED emitter, a significant (more than three times) increase in the transmission coefficient can be achieved. It is permissible to use a low-power semiconductor laser as an emitter, which will make it possible to create directed radiation and enhance the observed effects. Thus, there are sufficient grounds to believe that optimization of the design of semiconductor devices and integrated circuits using the proposed method can lead to an improvement in their static and dynamic characteristics.

Experimentally revealed two main disadvantages of the proposed method: 1) a long relaxation time after turning off the emitter; 2) the effect of fluctuations in the parameters of the emitter. These shortcomings are partially or even completely eliminated by constructive and technological techniques and methods.

The technical result consists in increasing the speed of semiconductor devices and integrated circuits by including in their design an emitter in the form of an LED or a low-power laser. The emitter is placed in the same housing together with the functional crystal of the transistor or integrated circuit. During operation, the functional crystal is affected by a continuous steady stream of photons emitted by the emitter. External radiation leads to a decrease in opening voltages and an increase in the gain of bipolar transistors, a decrease in threshold voltages and cutoff voltages of field-effect transistors, an increase in the speed and radiation resistance of these devices and integrated circuits based on them.

Claims (1)

A method for controlling the speed of transistors and transistor integrated circuits, which includes exposing the semiconductor structures of transistors and transistor integrated circuits to a photon flux from an LED or a low-power laser, while transistors, transistor integrated circuits, an LED or a low-power laser are placed in one housing, characterized in that the effect on semiconductor structures of transistors and transistor integrated circuits are carried out by a continuous stream of photons from an LED or a low-power laser during the operation of transistors and transistor integrated circuits.

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