JPH01297859A - Optical not circuit - Google Patents

Abstract

PURPOSE:To reduce the size of an electronic circuit and save power consumption by forming minute semiconductor elements monolithicly on one semiconductor substrate. CONSTITUTION:A P-N-P-N photothyristor 20 switched by an incident light and a P-N light emitting diode 21 are formed on one common semiconductor substrate. A common layer is used as the anode layer of the thyristor 20 and the anode layer of the diode 21. The gate absorbing layer and the cathode layer of the thyristor 20 and the light emitting layer and the cathode layer of the diode 21 are isolated from each other by element isolation layers. If a light input X is inputted to the thyristor 20 of this circuit, the thyristor 20 is in a conducting state. If a voltage is applied to so electric source terminal 24, a current applied to a resistor 17 is increased and a voltage applied to the anode of the diode 21 is declined. If the resistance of the resistor 17 is so selected as to have the declined voltage lower than the threshold voltage of the diode 21, the diode 21 does not emit a light when the thyristor 20 is in a conducting state and emits a light when the thyristor 20 is in a non-conducting state. With this constitution, the emitting and non-emitting states of the diode 21 contrary to the OFF and ON states of the thyristor 20 can be obtained.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an optical negation circuit, which is one of the most important circuits among the optical logic circuits required for realizing optical switching and optical computers. It is something.

(Prior Art) Conventional logic circuits have been made using electronic circuits mainly using transistors. Electronic circuits are expected to continue to develop both now and in the future, but in some areas their limits are beginning to appear. It is a logic circuit in which the number of wires connecting transistors is much larger than the number of transistors. Typical examples include massively parallel processors with a very large number of processors, and neurocomputers where elements are all connected and information is stored in the weights of those connections. In an attempt to break through the limitations of wiring in such electronic circuits, attempts have been made to improve the density of wiring using optical wiring and to make the wiring arbitrarily variable. For example, J. W. Gutsman et al.
an et al.) in the proceedings off the
Prodeed of the IEEE, 1984, volume 72, page 850.
Vol. 72, 1984) proposed the above-mentioned concept of optical wiring. Although this proposal has not been actually prototyped and is merely a proposed concept, it is an innovative attempt to improve wiring limitations using optical wiring. However, among these proposals, there is no specific proposal for an optical negation circuit, and there is also no other one that can be used practically. Practical means that it can be made smaller like electronic circuits, consumes less power, and can exchange information using light.
This means that the input also has the function performed by the output light.

(Problems to be Solved by the Invention) The above-mentioned optical negation circuit has a function that can be miniaturized like an electronic circuit, has low power consumption, and that input and output are performed using light so that information can be exchanged using light. The purpose of the present invention is to provide an optical circuit that has the following characteristics.

(Means for Solving the Problems) According to the first aspect of the present invention, a PNPN type optical thyristor that is switched by incident light and a PN type light emitting diode (including a diode tracer, hereinafter collectively referred to as a light emitting diode) are provided. ) formed on one common semiconductor substrate, and the anode layer of the optical thyristor and the anode layer of the light emitting diode are a common layer, and the gate absorption layer and cathode layer of the optical thyristor layer and the light emitting layer of the light emitting diode. and by being separated by a cathode layer or an element isolation layer,
According to the second invention, there is obtained a light negation circuit characterized in that the light emitting diode assumes a non-light emitting state and a light emitting state in response to the opposite states of the on and off states of the optical thyristor. A switching NPNP type optical thyristor,
A PN type light emitting diode is formed on one common semiconductor substrate, and the cathode layer of the photothyristor and the cathode layer of the light emitting diode are a common layer, and the gate absorption layer and anode layer of the photothyristor layer and the light emitting diode The light-emitting layer and the anode layer are separated by a device isolation layer, so that the light-emitting diode takes a non-light-emitting state and a light-emitting state in response to the on and off states of light incident on the optical thyristor. An optical negation circuit is obtained.

(Function) The function of the present invention will be briefly explained below using FIG. 2.

FIG. 2(a) is a circuit diagram of an optical negation circuit explaining the first aspect of the present invention. The constituent elements are optical thyristors 20
and a light emitting diode 21, a common resistor 17, and a resistor 19 in series with the light emitting diode. Here P
An NPN optical thyristor 20 is used, and the anode of this element, which is a P-type semiconductor, and the anode, which is a P-type semiconductor of a PN light emitting diode, are shared. A resistor 17 is placed between this common terminal and the positive power supply. A circuit having such a configuration constitutes the first invention. When the optical input X that is equal to or higher than the value level of the optical thyristor 20 is input to the optical thyristor 20, this thyristor becomes conductive.

If a stop voltage is applied to the power supply terminal 24, the current flowing through the resistor 17 will increase, and the voltage applied to the anode of the light emitting diode 21 will drop. The value of the resistor 17 is set so that this voltage is lower than the value voltage of this light emitting diode. Then, when the optical thyristor 20 is in a conductive state, the light emitting diode does not emit light. Further, when no light is input to the optical thyristor 20, this optical thyristor remains in a cut-off state. When a stopping voltage is applied to the terminal 24 in such a state, the resistor 1 is
The current flowing through 7 is reduced so that light emitting diode 21
The voltage on the anode side of the PN light emitting diode 21 increases.
exceeds the rising voltage and emits light. In this way,
The optical negation circuit is characterized in that a light emitting diode takes a non-light emitting state and a light emitting state in response to the opposite states of the on and off states of the optical thyristor. In such an optical negation circuit, since the PNPN element has a latch function, it is only necessary to apply a voltage to the terminal 24 when an output is required, and power consumption can also be reduced.

FIG. 2(b) is a circuit diagram of an optical negation circuit explaining the second invention of the present invention. The constituent elements are the same as those in the first invention, but an NPNP optical thyristor 2 is used as the optical thyristor.
The difference is that No. 2 is used, and the portion that is shared with the cathode, which is an N-type semiconductor, of this element is the cathode, which is an N-type semiconductor, of the 28 light-emitting diode.

Since the operation of light negation is the same as that of the first invention, the explanation will be omitted.

(Example) Next, an example of the present invention will be described in detail using the drawings. FIG. 1 is a diagram illustrating details of the first invention.

As the semiconductor substrate 11, a P-type GaAs semiconductor was used. A common resistance layer 17 made of high purity GaAs with a thickness of 5 microns was formed on this semiconductor substrate. The resistance value is almost 100
It was Ohm. In addition, P-type AlGa with a thickness of 2 microns
An As semiconductor layer 12 was formed on the top surface of the common resistance layer 17. Two devices were formed on this semiconductor substrate using this P-type AlGaAs semiconductor layer 12 as a common layer. In the left sectional view of FIG. 1, an optical thyristor was formed in the left half, and a light emitting diode was formed in the right half. The light emitting diode here is a surface emitting type LED without a resonator. The optical thyristor is of the PNPN type, and the light emitting diode is of the double heterojunction PN type. optical bistable ma)
In the IJ socks, the AlGaAs emitter layer made of a P-type semiconductor is shared with the P-type anode layer of the light emitting diode, and the P-type AlGaAs semiconductor layer 12 is used.

The gate absorption layer of the optical thyristor consists of an N-type GaAs layer 131 with a thickness of 1 micron, which is narrower than the forbidden band width of the collector layer, and a 0.0.
A double layer of 0.05 micron P-type GaAs layers was used.

This is because the optical input to the optical thyristor is efficiently absorbed by the gate layer. Then, on the P-type gate absorption layer 132 of the optical thyristor, a 2-micron-thick N-type G
An N cathode layer 133 made of aAlAs was used.

A GaAs layer with a thickness of 1 micron was also used for the light emitting layer 151 of the light emitting diode. This light emitting layer 151 is made of N
It is sandwiched between a P-type AlGaAs cathode layer 152 and a P-type AlGaAs anode layer 12 . The absorption layer 131 and the light emitting layer 151 were separated by an element isolation layer 14 made of polyimide. A high-purity GaAlAs resistance layer 19 was formed on the N-type AlGaAs cathode layer 152 to have a resistance value of 10 ohms.

P-side electrode 18 of the optical thyristor and light-emitting diode, and N
The side electrode 16 is common. The N-type electrodes each have an optical thyristor entrance 134 and an optical thyristor exit 134.
53 is opened, through which the incident light 135 and the outgoing light 154 enter and exit.

With the above-described configuration, the optical thyristor 20 and the light emitting diode 21 shown in FIG. 2(a) are connected in series with the common 100 ohm resistor 17 and the light emitting diode. A 10 ohm resistor 19 was monolithically formed on the semiconductor substrate.

In this embodiment, a PNPN optical thyristor 20 is used,
The anode of this element, which is a P-type semiconductor, and the anode, which is a P-type semiconductor, of the 28 light emitting diodes are shared. And between this common terminal and the 5 volt power source, 100
The ohmic resistor 19 is narrowed. Optical thyristor-20
When an optical input X having a wavelength of 0.78 microns or more is input to the optical thyristor 20, this thyristor becomes conductive. Then, the current flowing through the resistor 17 increases, and the voltage applied to the anode of the light emitting diode 21 drops. The value of the resistor 19 is set to 1 kilohm so that this voltage is lower than the voltage value of 1.5 volts of this light emitting diode. Then, when the optical thyristor 20 is in a conductive state, the light emitting diode does not emit light. In addition, the optical thyristor 20
When the optical input becomes a level below the value of the optical thyristor 20, this optical thyristor enters a cut-off state, the current flowing through the resistor 19 decreases, and therefore the voltage on the anode side of the light emitting diode 21 increases, causing PN light emission. The threshold voltage of the diode 21 exceeds 1.5 volts, and light is emitted. In this way, the optical output is always in the opposite state to the optical input.

In the embodiments described above, minute elements are monolithically formed on a semiconductor substrate, so they can be miniaturized like electronic circuits, have low power consumption, and can be inputted so that information can be exchanged by light. An optical negation circuit is obtained whose functions are performed on the output light.

FIG. 3 is a diagram for explaining the second invention in detail.

As the semiconductor substrate 31, an N-type GaAs semiconductor was used. A common resistance layer 37 made of high purity GaAs and having a thickness of 5 microns was formed on this semiconductor substrate. The resistance value was approximately 1 kilohm. In addition, 2 micron thick N-type AlGa
An As semiconductor layer 32 was formed on the top surface of the common resistance layer 37. Two devices were formed on this semiconductor substrate using this N-type AlGaAs semiconductor layer 32 as a common layer. In the left sectional view of FIG. 3, an optical thyristor was formed in the left half, and a light emitting diode was formed in the right half.

The constituent elements are the same as those of the first invention, but the NPNP optical thyristor 27 is used as the optical thyristor, and the part that is common to the anode of this element, which is a P-type semiconductor, is the N of the PN light-emitting diode. The difference is that the cathode is a shaped semiconductor. In this embodiment as well, the optical output is always in the opposite state to the optical input state.

In the embodiments described above, subtle elements are monolithically formed on a semiconductor substrate, so they can be miniaturized like electronic circuits, consume less power, and can also be inputted so that information can be exchanged by light. An optical negation circuit is obtained whose functions are performed with the output light.

It is clear that the thickness and composition of each layer described in the first and second embodiments are not particularly limited.

In the first and second embodiments above, G a As
/GaAIAs-based semiconductor was used, but
The present invention is not limited to this material system, and InP/InGaA
Other compound semiconductors such as sp-based ones are also possible.

In the first and second embodiments described above, an LED without a resonator was used as the light emitting diode, but a diode laser having a resonator configuration and capable of producing a laser output may also be used.

(Effects of the Invention) As explained above, according to the present invention, minute elements are monolithically formed on a semiconductor substrate, so it can be miniaturized like an electronic circuit, has low power consumption, and is light An optical negation circuit has been obtained which has the function of inputting and outputting light so that information can be exchanged.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining the first invention in detail, 11... P-type GaAs semiconductor substrate, 12...
...P-type AlGaAs anode layer, 131/N-type Ga
As-based absorption layer, 132 ・P-type GaAs-based absorption layer, 133 ・N-type A
lGaAs cathode layer, 134... Optical thyristor entrance port, 14... Element isolation layer, 151-GaAs light emitting layer, 152-N type AlGaAs cathode layer, 153... Photodiode exit port, 135...・Incoming light, 154... Outgoing light, 16... N-type electrode, 17... GaAs common resistance layer, 18...
・P-type electrode, 19...Represents GaAlAs resistance layer. FIG. 2(a) is a circuit diagram of an optical negation circuit explaining the first invention of the present invention, and FIG. 2(b) is a circuit diagram of an optical negation circuit explaining the second invention of the present invention. , 20...PNPN optical thyristor, 21...
... PN light emitting diode, 22 ... NPNP optical thyristor, 24 ... power supply terminal, 17 ... common resistance, 19 ... resistance. FIG. 3 is a diagram for explaining the second invention in detail, 31... N-type GaAs semiconductor substrate, 32...
...N-type AlGaAs cathode layer, 331 ・P-type G
aAs-based absorption layer, 332 - N-type GaAs-based absorption layer, 333 - P-type AlGaAs anode layer, 334
... Optical thyristor entrance opening, 335 ... Incident light, 34 ... Element isolation layer, 351 - Ga As light emitting layer, 352 - P-type AlGaAs anode layer, 353 ...
Photodiode output port, 335...Incoming light, 354...Outgoing light, 36...N-type electrode, 37...GaAs common resistance layer, 38...
・N-type electrode, 39...Represents GaAlAs resistance layer.

Claims (2)

[Claims] (1) A PNPN type optical thyristor that switches according to incident light and a PN type light emitting diode (including a diode laser, hereinafter collectively referred to as a light emitting diode) are formed on one common semiconductor substrate, and the optical thyristor is The anode layer and the anode layer of the light emitting diode are a common layer,
An optical negative circuit characterized in that the gate absorption layer and cathode layer of the optical thyristor layer and the light emitting layer and cathode layer of the light emitting diode are separated by an element isolation layer. (2) An NPNP type optical thyristor that is switched by incident light and a PN type light emitting diode are formed on one common semiconductor substrate, and the cathode layer of the optical thyristor and the cathode layer of the light emitting diode are a common layer. and a gate absorption layer and an anode layer of the optical thyristor layer and a light emitting layer and an anode layer of the light emitting diode are separated by an element isolation layer.