JPS6222548B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to improvements in photoelectric conversion devices.

Conventionally, photoelectric conversion devices have been made using materials such as Cu, Zn, etc., which provide a deep energy level, as shown in Figure 1.
First and second conductive layers 2 and 3 are added to a semiconductor 1 made of Ge, for example, into which impurities such as
However, the area between the conductive layers 2 and 3 of the semiconductor 1 is formed as a light irradiation area 4 where light is irradiated.
Each is attached as an electrode, and a conductive layer 2
When the light 7 is externally irradiated onto the light irradiation area 4 with the bias power supply 6 connected through the load 5 between the irradiation area 4 and 3, a current corresponding to the amount of light irradiation is supplied to the load 5. A device having a configuration that provides a photoelectric conversion function has been proposed.

However, in the case of such a photoelectric conversion device, conductive layers 2 and 3 are attached to a semiconductor 1 into which an impurity giving a deep energy level is introduced so as to form a light irradiation region 4 between them. However, the photoelectric conversion function does not have an amplification function, and therefore the sensitivity of the photoelectric conversion function is low.

Further, as the bias power supply 6, a power supply capable of obtaining a relatively high voltage is required, and in order to obtain the required amplified current, in addition to the photoelectric conversion device,
In addition to requiring a current amplifier, the amplified current obtained from the current amplifier also amplifies the noise contained in the current obtained from the photoelectric conversion device, and therefore the amplified current obtained from the current amplifier It had drawbacks such as not having a good S/N ratio.

Therefore, the present invention proposes a novel photoelectric conversion device free from the above-mentioned drawbacks, which will become clear from the detailed description below.

FIGS. 2 and 3 show an example of the principle of the photoelectric conversion device according to the present invention, in which a substrate 11 made of semi-insulating silicon crystal into which impurities made of Au, Ni, or Be are introduced to provide a deep energy level. and has a main surface 12 in its substrate 11.
From the side, regions 13 and 14 into which an acceptor impurity made of boron is introduced at a high concentration, and region 15 into which a donor impurity made of phosphorus is introduced at a high concentration.
and 16 are formed such that a region between regions 13 and 14 and a region between regions 15 and 16 of substrate 11 are formed as light irradiation regions 17 and 18, respectively.

Further, an insulating film 19 made of an oxide of the material of the substrate 11 and having a light-transmitting property is formed over the entire main surface 12 of the substrate 11 by thermal oxidation treatment of the substrate 11. Conductive layers 20 and 21 made of evaporated gold layers with a thickness of 100 Å are formed on the main surface 12 of the substrate 11 on the light irradiation areas 17 and 18 with an insulating film 19 interposed therebetween. .

Furthermore, a conductive layer 23 as an electrode is applied to the region 13 through a window 22 pre-drilled in the insulating film 19, and a conductive layer 23 as an electrode is also applied to the region 16 through a window 24 pre-drilled in the insulating film 19. A conductive layer 25 as an electrode is ohmically applied to the insulating film 19, and regions 14 and 15 are ohmically connected to the regions 14 and 15 through windows 26 and 27 previously drilled in the insulating film 19, respectively. The conductive layers 20 and 21 are electrically interconnected by an extended conductive layer 28 as a wiring layer, and furthermore, the conductive layers 20 and 21 are connected to a conductive layer 29 extending integrally therewith. Therefore, they are electrically connected to each other,
In addition, regions 14 and 15 and conductive layers 20 and 21
is connected to the conductive layers 21 and 28 and the insulating film 1 is connected to the conductive layers 21 and 28.
They are electrically connected to each other via a resistive layer 30 extending above the resistive layer 9 and having a high resistance.

The above is an exemplary basic configuration of the photoelectric conversion device according to the present invention.

According to the photoelectric conversion device according to the present invention having such a configuration, the regions 13, 17, and 14, the conductive layer 20, and the region under the conductive layer 20 of the insulating film 19 are used as a drain region and a drain region, respectively. P-channel type MIS, which has a P-type channel forming region, a source region, a gate electrode, and a gate insulating layer.
This constitutes an element Q1 having a type transistor configuration.

Further, the regions 15, 18, 16, the conductive layer 21,
and an element Q2 having an N-channel MIS transistor configuration in which the regions under the conductive layer 21 of the insulating film 19 serve as a drain region, an N-type channel forming region, a source region, a gate electrode, and a gate insulating film, respectively. It consists of

These elements Q1 and Q2 are connected in series by a conductive layer 28, and a region 14 as a source region of element Q1 and a region 14 as a source region of element Q
The region serving as the drain region of 2 is the conductive layer 2
8, the elements Q1 and Q2 are connected in series, and the conductive layer 20 serves as the gate electrode of the element Q1 and the conductive layer 20 serves as the gate electrode of the element Q2. Since the conductive layers 21 are connected to each other by the conductive layer 29, the conductive layer 23 connected to the region 13 as the drain region of the element Q1 and the conductive layer 23 as the source region of the element Q2 are connected to each other by the conductive layer 29. The conductive layer 25 is used as a pair of power supply connection terminals, and the conductive layer 29 interconnects the conductive layer 20 as the gate electrode of the element Q1 and the conductive layer 21 as the gate electrode of the element Q2. A so-called CMOS inverter is configured, which has an input terminal and a conductive layer 28 that interconnects a region 14 serving as a source region of element Q1 and a region 15 serving as a drain region of element Q2 as an output terminal. There is. However, in this case, the conductive layer 29 as the input end of the CMOS inverter is
Since it is connected to the conductive layer 28 as the output end of the inverter via the resistive layer 30, it has a configuration in which the voltage at the output end of the CMOS inverter is fed back to the input end of the CMOS inverter.

Then, a resistive layer 30 is added to the conductive layers 20 and 21.
It has a configuration in which a voltage at the midpoint of the connection between elements Q1 and Q2 is applied through.

Therefore, between the regions 13 and 16, the conductive layer 2
If a bias power supply 31 with the conductive layer 23 side being positive is connected through terminals 3 and 25, and the voltage is adjusted appropriately, the devices will turn off even if both Q1 and Q2 are in the on state. The conductive layer 28 serves as the output terminal of the CMOS inverter and the conductive layer 23 serves as the power supply connection terminal.
or 22, a voltage having a value approximately 1/2 of the voltage of the bias power supply 31 is obtained.

However, from such a transition state, the conductive layers 20 and 21,
When light 32 is irradiated from the outside through the area under the conductive layers 20 and 21 of the insulating film 19, an amount of carriers (electrons) corresponding to the irradiation amount of the light 32 is emitted.
is excited in the region 17 as the P channel forming region of the element Q1 and the region 18 as the N channel forming region of the element Q2.

Therefore, if the impurity that provides a deep energy level in the semiconductor substrate 11 is an impurity that provides an acceptor level, the above-mentioned Carrier (electronic)
A negative space charge is generated in accordance with the amount of
Element Q2 with N-channel MIS transistor configuration
In this case, the OFF state is closer to the OFF state.

Therefore, the voltage seen between the conductive layers 28 and 25 becomes higher depending on the irradiation amount of the light 32 compared to the case where the light 32 is not irradiated, and the voltage seen between the conductive layers 28 and 23 becomes higher. Compared to the case where the light 32 is not irradiated, the amount becomes smaller depending on the irradiation amount of the light 32.

Therefore, the conductive layer 28 between elements Q1 and Q2
A voltage that changes depending on the change in the amount of light 32 irradiated is obtained between the conductive layer 23 of element Q1 or the conductive layer 24 of element Q2.

Therefore, according to the photoelectric conversion device according to the present invention shown in FIGS. 2 and 3, with the bias power supply 31 connected between the regions 13 and 16, the light irradiation region 1
7 and 18 from the outside through the conductive layers 20 and 21 and the area under the conductive layers 20 and 21 of the insulating film 19, a voltage corresponding to the amount of irradiation is applied to the area. 14 and 15 and area 13
or 16.

The amount of change in voltage in this case is such that when elements Q1 and Q2 are connected in series, when element Q1 becomes more on, element Q2 becomes more off. Based on this, the voltage obtained is the same as that obtained from the output terminal of a CMOS inverter, which is obtained differentially, so it is sufficiently large.

Therefore, according to the photoelectric conversion device according to the present invention shown in FIGS. 2 and 3, it can be said that the photoelectric conversion function has an amplification function, and therefore the sensitivity of the photoelectric conversion function is the first. This is significantly higher than the conventional photoelectric conversion device described above in the figure.

Incidentally, when the photoelectric conversion device according to the present invention shown in FIGS. 2 and 3 has the configuration of the specific example described above, the current flowing in the region 13 or 16 with respect to the voltage V _D of the bias power supply 31 is 1st
In the case of the conventional photoelectric conversion device shown in the figure, we actually measured how many times the amplification factor A of the current supplied to the load 5 can be obtained, and the results shown in FIG. 4 were obtained.

From this result as well, it is clear that the photoelectric conversion device according to the present invention provides a much higher sensitivity of the photoelectric conversion function than the conventional photoelectric conversion device.

Further, according to the above-described photoelectric conversion device according to the present invention, as is clear from the above-mentioned FIG. 4, a power source capable of obtaining a high voltage is not required as the bias power source 31.

Furthermore, according to the photoelectric conversion device according to the present invention,
As mentioned above, it can be said that the photoelectric conversion function has an amplification function, so even if a separate amplifier is not required or is required, an amplifier with a small amplification degree can be used to adjust the amount of light 32 irradiated. A varying amplified voltage can be obtained, and therefore, the amplified voltage can be obtained as a voltage with good S/N.

Note that the above description is merely an example of the present invention, and in addition to using a semi-insulating silicon crystal substrate into which Au, Ni, or Be is introduced as the substrate 11, other impurities that provide a deep level may be introduced. Even if the semi-insulating semiconductor substrate shown in FIG. Even if phosphorus as a shape impurity is replaced with another donor shape impurity, the same excellent effects as described above can be obtained, and various other modifications and changes can be made without departing from the spirit of the present invention. will be able to do it.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a conventional photoelectric conversion device. FIG. 2 is a schematic plan view showing an example of a photoelectric conversion device according to the present invention. FIG. 3 is a cross-sectional view along the line. FIG. 4 is a voltage-amplification characteristic for explaining the photoelectric conversion device according to the present invention. 11...Semi-insulating semiconductor substrate, 12...Main surface,
13-18...Region, 19...Insulating film, 20,2
1, 28... conductive layer, 30... resistance layer.

Claims (1)

[Claims] 1. First and second substrates made of a semi-insulating semiconductor into which impurities providing a deep energy level are introduced, into which acceptor-type impurities are introduced at a high concentration from the main surface thereof. and third and fourth regions into which donor-type impurities are introduced at a high concentration are a region between the first and second regions and a region between the third and fourth regions of the substrate. are formed to form first and second light irradiation regions, respectively, and are formed on the main surface of the substrate through an insulating film having a light-transmitting property on the first and second light irradiation regions. , first and second conductive layers having translucency are formed, the second and third regions are electrically connected to each other, and the first and second conductive layers are electrically connected to each other. the second and third regions and the first and second conductive layers are electrically connected to each other via high resistance, and the first and fourth regions The first and second conductive layers and the first and second conductive layers of the insulating film are applied to the first and second light irradiation regions with a required bias power source connected therebetween. When light is irradiated from the outside through the region under the layer, a voltage corresponding to the amount of light irradiated is generated between the second and third regions and the first or fourth region. A photoelectric conversion device characterized by being obtained.