JPS5931057A - Semiconductor device - Google Patents

Abstract

PURPOSE:To obtain a photoelectric conversion device of high withstand voltage by combining a single crystal semiconductor with a non-single crystal semiconductor. CONSTITUTION:An Si having the plane (100) is used as the single crystal semiconductor. Buried semiconductor regions 8 and an N type semiconductor layer 7 are formed on a P type semiconductor on a substrate 1. Next, an Si oxide film 4 and P type semiconductor layers 2 are formed. The N type non-single crystal semiconductor layer 12 is formed, and then a clear conductive film 13 is formed. Thereat, the film 13, the layer 12, and an I-layer 11 are etched by a photo mask. Finally, an emitted lead 14 is manufactured by means of the film 13 which composes the emitter.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor device formed by combining a single crystal semiconductor and a non-single crystal semiconductor, and particularly to an integrated structure of a photoelectric conversion device having a phototransistor function.

The present invention comprises a single-crystal semiconductor base on a collector provided on a single-crystal semiconductor, and a non-single-crystal semiconductor that generates a photovoltaic force when irradiated with light, in which a hydrogen or halogen element having an emitter function is added to the base. The present invention relates to a semiconductor device provided with.

As a non-single-crystal semiconductor having such an emitter function, the present invention is directed to an intrinsic or substantially intrinsic 00 to 10"c-doped semiconductor with a low concentration of KP or N-type impurity) having a large light absorption coefficient. The present invention relates to a semiconductor device including a semiconductor for generating carriers (hereinafter referred to as a single YCX type semiconductor layer or one layer) and a P or N type semiconductor layer having an emitter electrode function on this semiconductor layer.

The present invention further provides a P- or N-type semiconductor layer with a semiconductor having a wider energy band than a single layer, such as a semiconductor using B i, x C1-2 (0<xi 1), or a photonic layer. By using a polycrystalline semiconductor with a micro-polycrystal or uniaxial single-crystalline fiber structure with a size of 5 ()-200^, which has a low absorption loss, light incident from the emitter side reaches the effective KI layer and is photosensitive. It is characterized by generating a large number of carriers.

Further, in the present invention, a single crystal semiconductor, particularly a silicon semiconductor, has an energy band d of 1°1 eV, and although it is possible to detect infrared light, the visibility of visible light is not sufficient.

Even with shattered infrared light, photocarriers cannot be generated sufficiently because the light absorption coefficient of single crystal semiconductors is small. For this reason, we have further improved the conventionally known phototransistor using a single-crystal semiconductor, and we have developed a depletion layer region between the emitter of the photosensitive region or the emitter base (in this specification, these are collectively referred to as the emitter function). It is characterized by the use of a non-single crystal semiconductor with a large light absorption coefficient.

In the optical energy band of 1.6
~1.8θV, and its light absorption coefficient is also about 10 times larger than that of single crystal silicon. Therefore, it has extremely high conversion efficiency for visible light, and its photosensitivity characteristics are the same as human visual sensitivity, so it can be used as a substitute for human eyes with a light amplification function.

On the other hand, one layer as a photoactive semiconductor layer is an amorphous or semi-amorphous semiconductor and the material is germanium with a voltage of 1 to 1.2 eV, and S1xGe,
(In Olx (1), any wavelength band between 1.1 and 1.8 eVO is further defined as K Si, xSn, -4 (0<x<1)
In this case, any wavelength band between 0.5 and 1°8 eV can be selected.

For this reason, the composite semiconductor device of a single crystal semiconductor and a non-single crystal semiconductor having an integrated structure of the present invention is capable of transmitting visible light, infrared light, red, blue, green, etc. by using a filter. By providing selectivity, it can be used to configure image sensors, solid-state image pickup tubes, etc.

It can be tightened.

Furthermore, by making this integration into a uniaxial array,
It can be used as an optical sensor assembly having the same visibility as the human eye. For this reason, such an integrated body is effective as a light-receiving sensor for facsimile, and by reducing the element size and using microscopic 1U-14if, it can be ) It is possible to specify an address and store a digital signal in the analog Φ Company 1Mo system.

Furthermore, since the present invention uses a wholesale crystal semiconductor between the base and collector where reverse bias is applied, the frequency response speed is fast.
As a light receiving sensor for optical fiber communication, it is convenient not only for infrared light but also for visible light. Especially visible light K
(111), so it has the characteristic that it can be converted into an electrical signal with visibility of the same color as the naked eye, for medical cameras and the like.

In addition, regarding the voltage relationship, the compensation pressure Tf between the emitter and base is
In the fy~5VQ@ direction, only 0° and 2V is applied, so there is no problem in terms of reliability. On the other hand, by removing lattice defects between the base and the collector at ~200 V, a breakdown voltage of 10 A or less with a leak of 10 A or less can be withstood in practical use without any problems even at 20-200 V.

Therefore, in the forward bias region, a non-single crystal semiconductor doped with hydrogen or a halogen element is used in the depletion layer region, and in the reverse bias region, the lateral pressure is increased and the reverse bias Leak from spear] 0-10A
It is possible to measure the decrease in (in the case of OV application).If a non-single crystal semiconductor is used in the depletion layer region between the base and the collector, the reduction in ]-0~1OA (in the case of 5V application) can be measured. Considering that the single-crystal semiconductor of the present invention is combined with a non-single-crystal semiconductor, the advantages of each are mutually brought out, and the shortcomings of each are compensated for, so that the compositional effect can be improved. There are some notable ones.

Previously, four transistors were made only from single-crystal semiconductors. A typical vertical sectional view is shown in FIG.

As is clear from the drawing, a base (2) and an emitter (3) are diffused into a single crystal semiconductor substrate (1) using planar technology, and a silicon oxide insulating film (4) is provided with a K opening to form an electrode lead for the emitter. (5), base electrode lead (6)
In addition, most of the substrate is used as a collector ('7), and an electrode (8) is provided thereon.

In such a structure, for incident light 00, the emitter is N+, and its Pg (optical energy band width is hereinafter referred to as ICg) is −01 eV in silicon.
Therefore, there is a large amount of light absorption loss in this emitter region. In addition, in silicon, the active region (depletion layer between emitter and base) due to light irradiation (1o) has a high concentration of N? Type emitter (impurity concentration 10'' to 101'-cm) - P-type base (impurity concentration 10cm), so it is extremely thin.For this reason, it is a single crystal indirect transition type, and even though its absorption coefficient is small. In other words, although it is necessary to be thick to generate a large number of photocarriers, this depletion layer is as thin as ~0.1μ.For this reason, the probability of photocarrier generation (quantum efficiency) is small.

In addition, in the case of single crystal silicon, since the voltage is 1°1 eV, it is far from the human visibility characteristic.

Because of these drawbacks, their use in mechatronic optical sensors (9) and the like has not been satisfactory, and phototransistors with even better photosensitivity have been desired as light-receiving elements for optical communications.

The present invention compensates for these drawbacks.

Examples are shown below according to the drawings.

FIG. 2 is a vertical sectional view showing the manufacturing process of the semiconductor device of the present invention.

In Figure 2 (A), as a single crystal semiconductor (100
) surface was used. The substrate (1) has a recessed semiconductor region (8) formed by a selective diffusion method having a collector function of a P-type semiconductor upper part KN, and a recessed semiconductor region (8) of 0.2 to 2μ (typically N-type (including 1-type or N-type) semiconductor (7
) and more. Next, place the image shown in Figure 2 (B) on this board.
As shown in the figure, a film having a masking effect against oxide gases, such as silicon oxide (0 to 200X) and silicon nitride (500 to 1000K), is selectively embedded in this soil to form a soil sensor (8). was formed on the area constituting the area.

After this, the semiconductor was heated to 900-1100°O with oxygen (5-1
A 0(10) elemental film (4) was formed to a thickness of O05 to 1.5μ.Next, using this as a mask, P-type impurities were selectively doped to a thickness of 200λ to 1μ by ion implantation. A P-type semiconductor layer (2) was formed.

Thus, the single crystal semiconductor (1) in FIG. 2(B) has an N-N type collector selectively provided in a substrate having a collector function, and a P type base (1) made of a single crystal semiconductor on top of the N-N type collector.
2) is configured. Thereafter, the silicon oxide and silicon nitride mask (1) on this base (2) was removed to expose the single crystal semiconductor surface.

Next, in this step, a substantially intrinsic non-single-crystal semiconductor layer doped with an intrinsic or valent impurity such as boron to a concentration of 10 to 10 cm is formed on the single-crystal semiconductor by 500 cm.
It was formed to a thickness of ~500 mm by plasma CVD.

This plasma CVD method is used to produce a semiconductor whose main component is amorphous or semi-amorphous silicon to which hydrogen or a halogen element such as fluorine or chlorine is added as a non-single crystal semiconductor. Silane or silicon fluoride was applied at a frequency of '1.3.56 M'H2 and formed by a glow discharge method at a temperature of 100-350''C.

Regarding this semi-amorphous semiconductor, a patent application (Semi-Amorphous Semiconductor Patent Application No. 51263
88).

Furthermore, an N-type non-single crystal semiconductor layer 0→ having a fiber structure was formed on this upper surface to a thickness of 1-00 to 300 Å.

This semiconductor having a fiber structure has single crystallinity in the -axis direction, and even at a low temperature of 200 to 250"O, the semiconductor has 5 to 10
It can be made with low W high frequency output. This semiconductor having a fiber structure is disclosed in the patent application (Semiconductor having a fiber structure and its manufacturing method), which is the application of the present invention.
-8'i'801615'7°5.24)K is shown.

Although the semiconductor with this fibrous structure has an optical energy band l] of 1.5 to 1.8θ, its light absorption coefficient is as small as that of a single crystal, and its trench electrical conductivity is also lO
Since it has an extremely large value of ~300 (Acm), it is convenient for forming the emitter of the phototransistor of the present invention.

When this N″ layer is formed of an amorphous silicon semiconductor,
Its absorption coefficient is large, making it undesirable. For this reason, as this semiconductor, a micro polycrystal (crystal grain size 100 to 300 to -i: crystal grain size: 100 to 300 to -i) or a semiconductor having the above-mentioned fiber structure is preferable because silicon alone has a small absorption coefficient.

In addition, when using an amorphous semiconductor, 1 layer 0])
The energy band width, which is larger than K, is 5ixC・incline(0ri×
1) etc. to form W (N-type semiconductor layer)-N (
I type semiconductor layer) E Eg −NALLOW Eω from α
In order to increase the light absorption in this N-type semiconductor layer, for example, ITO (tin oxide doped with 0 to 1.0% tin oxide was formed by vapor deposition. At this time, ITO was added using a photomask).
,■ToQ3. 0 N+ layers, 0 steps]) was selectively etched.

Furthermore, as shown in FIG. 2 (0), this semiconductor is coated with photoresist, holes are selectively drilled, aluminum is vacuum-deposited in the holes, and the emitter is formed by lift-off. An emitter lead 0→ was prepared from the transparent conductive film electrode 0'3.

The purpose of this embodiment is to prevent the light transmittance of the aluminum electrode film from decreasing.

Finally, silicon oxide (not shown) was overcoated to a thickness of about 0.5 microns to improve reliability.

This silicon oxide was also formed by a plasma vapor phase method or a vacuum evaporation method. The temperature at which the non-single crystal semiconductor layer is formed on the substrate is 30°C.
The temperature was kept at 0° C. or lower to prevent a decrease in reliability due to release of elements for neutralizing recombination centers such as hydrogen in the semiconductor to the outside.

In the drawing, a base (2), a collector (7),
(8) is made of a single crystal semiconductor (1), and the regions that constitute the emitter function are the emitter 0 and the active layer (1◇) are both made of a non-single crystal semiconductor (3).Transparent conductive film 03
Light (]0) is irradiated from the side, and electrons and holes are generated.

At this time, a forward bias was applied between the base (2) and the emitter 02, and a reverse bias of 5 to 5°V was applied between the base (2) and the collector (7). By doing this, we were able to create over 5,000 phototransistors.

Of course, when no light irradiation is performed, it can function as a simple transistor, and even in such a case, the emitter H, (1]) (1 , 7 to 2 eV) has a large energy band l], so holes flowing in the opposite direction from the base to the emitter are blocked. I was able to make an excellent width increase.

In particular, in this example, since the active layer is made of amorphous or semi-amorphous silicon, the visibility is the same as that of the human eye, and a so-called unprecedented visible light phototransistor is mounted on two substrates ( 1) We were able to create an integrated structure in the soil. Depending on the application, the element type of this integration is
It goes without saying that it is possible to enlarge in the left-right direction and front-back direction in the drawing.

Example 2 In this example, non-single crystal germanium was used to form the active semiconductor layer 0 in FIG.

As a result, its energy band width is 1 eV, and since it is a non-single crystal semiconductor, its absorption coefficient is also large. For this reason, it was an excellent infrared sensor.

That is, after forming the structure shown in FIG. 2(A), germane was introduced at a temperature of 200 to 30 σC by a plasma vapor phase method, and the base (2) soil K was laminated to a thickness of 500 to 5000 λ. Furthermore, the emitter α uses a silicon non-single crystal semiconductor having an N fiber structure. Thus, to the emitter, '7 eV) - the active layer α. Since it had a W-N structure (0 eV) and the light absorption coefficient of the N+ layer was small, all the infrared light could be supplied to the active germanium layer.

The steps other than this step were based on Example 1K.

Thus, hIL2-10 with reverse leakage of 162A or less for infrared detection? o A phototransistor can be made, and since it is a special KNPN (including NIp#N type), the carriers are electrons, and its frequency response speed is fast.
It has also become possible to use it as a light receiving sensor for optical communications.

Embodiment 3 In this embodiment, the NIP N-junction phototransistors of Embodiment 1 are arranged in a matrix structure to form a phototransistor array.

FIG. 3 shows the circuit diagram.

Figure 4 is a plan view (A) of an array made according to the circuit diagram in Figure 3, a vertical sectional view (B) along A-A', and B-B.
' shows a vertical sectional view (C).

In FIG. 3, an NPN transistor (N I pl
N transistors may also be used. Fi here, NIPI
N.

The base of (1) is not connected, but the secondary array of this phototransistor has one transistor connected to the emitter as shown in (a). It has a diode structure with a photodiode for photoelectric conversion using a diode between the bases and a diode for circuit selection using a diode between the base and collector in the opposite direction.This is because when reading, this diode for circuit selection ( The blocking diode) is turned on and a photocurrent flows through the load resistor R.

At this time, it is thought that the light conversion photodiode was continuously exposed to light from the outside, so the voltage applied in the opposite direction during the previous readout charged the capacitor 0→ of the photodiode, and the charge was transferred during this time. During readout, the capacitor of this photodiode is charged by the amount discharged by the photocurrent generated, resulting in a so-called accumulation effect.

Due to this cumulative effect, the 101
It was possible to increase the sensitivity by as much as ~IO'.

That is, the phototransistor constitutes a current amplification circuit having a grounded emitter structure as shown in FIG.

FIG. 4 shows this semiconductor device.

As is clear in the drawing, the irradiation light (10) [substrate (1
) side and below the transparent first electrode 0 pier KN(1
2IO2) P (2) N (8) is provided in a matrix configuration on this single crystal substrate as in Example 1.

The buried insulator provided between the plurality of phototransistors has its upper surface electrically isolated from the electrode leads of the microelectrode, and is shielded from light to prevent the semiconductor substrate (]) from being irradiated with light. By making each element -
This is effective for further improving the contrast of images.

As is clear from the drawing, when the collector (8) and the collector lead (which also serves as a buried N region) are provided in the Y direction, emitter 0■, emitter electrode (1', IJ-
It is set in the X direction, and its intersection is one)
It constitutes the first transistor (a).

Therefore, these semiconductor devices were overcoated with moisture-resistant resin (not shown) to a thickness of 0.5 to 3 μm to improve their reliability.

Each i-transistor (a) was implemented with PN junction isolation and buried insulator with reverse bias between the substrate and collector, as seen in single crystal semiconductors.

The compound isolation with K
It is shown.

In other words, the phototransistor array can be fabricated in exactly the same process as in Example 1, without requiring any further precise mask alignment using photoetching. In addition, by covering the transparent conductive film of the phototransistor and forming an aluminum electrode 04, it is possible to configure a transistor with a high emitter F8g and high h4e, which completely new logic circuits such as peripheral decoders. A major feature is that it does not require the use of a photomask. In addition, in Example 1, if the step of forming a P-type base is omitted by using one type of photomask and the transparent conductive film is covered with an aluminum electrode, the region is N
"(8) -N-(7)-Work0■-N" (1■-Transparent conductive film 01-Aluminum electrode 0→, T-type non-single crystal semiconductor layer R4" 44 was used. It is possible to make a resistor in the vertical direction.

This allows the load resistance for configuring the logic circuit to be created in the vertical direction rather than in the horizontal direction, which has conventionally been known for bipolar ICs. This is extremely effective for miniaturizing the area.

This drawing shows a two-dimensional phototransistor array, and when used in an image sensor, etc., one layer is made of non-single crystal silicon (1,6~).If it is 80, its visibility is the same as that of the human eye. Therefore, it is possible to obtain the same wavelength sensitivity as human visible light.A -dimensional phototransistor array is fabricated by making only a portion of the section A-A' in Figure 4, and used in a computer card reading sensor, etc. You can.
(Also, it is a feature of the present invention that an integrated matrix array for infrared light using bipolar transistors as shown in Example 2 is constructed around the phototransistor.

In this embodiment, each transistor has an integrated structure in which three types of filters, such as red, blue-yellow, or red, green, and yellow, are arranged alternately, and each color sensitivity can be selected and detected. By doing so, it can also be used as a color image sensor.

Such a semiconductor device has become capable of color discrimination similar to that of the human eye, and its signals can now be detected with an increase of 11] (~).

As is clear from the above, the present invention combines the features of single-crystal semiconductors and those of non-single-crystal semiconductors to achieve unprecedented high breakdown voltage, minimal leakage, and visible leakage. was able to create a photoelectric conversion device with high light sensitivity that matches the human eye.

Furthermore, the emitter side can be used as a base compared to the collector side.

In embodiments of the invention, NPN, NIPN or NI
It is a PIN type. This is because the carrier mobility of a non-single crystal semiconductor is only several tenths of that of holes compared to electrons. However, PNP type (PINTP) using this hole
Needless to say, it is also possible to create a mold (including a mold).

[Brief explanation of the drawing]

FIG. 1 shows a vertical sectional view of a conventional phototransistor. FIG. 2 shows the manufacturing process of the semiconductor device of the present invention. FIG. 3 shows a circuit diagram when the integrated semiconductor device of the present invention is made into a 7-trix structure. FIG. 4 shows a plan view and a vertical sectional view of a semiconductor device corresponding to FIG. 3 of the present invention.

Claims (1)

[Claims] 1- A base consisting of a plurality of filler layers of opposite conductivity type having a collector function provided on a conductivity type single crystal semiconductor substrate, and a hydrogen or halogen element having an emitter function on the base. A semiconductor device comprising a plurality of non-single crystal semiconductors that generate photovoltaic force upon irradiation with added light. 2. In claim 1, a plurality of recessed regions of opposite conductivity type having collector and lead functions arranged in the X direction provided in a single crystal semiconductor substrate of − conductivity type, and a buried phantom A base made of a single crystal semiconductor layer on or above the t-acid region which is gaseously separated by an insulator, and a hydrogen or halogen element having an emitter and a lead function arranged in the direction KX of the paste are added. 1. A semiconductor device having an integrated structure in which a phototransistor is formed at the intersection of the X direction and the Y direction, in which a plurality of non-single crystal semiconductor layers that generate a photovoltaic force upon irradiation with light are provided. 3. In claim 1 or 2, the plurality of non-single-crystal semiconductors having an emitter function include an intrinsic or substantially intrinsic semiconductor layer in close proximity to the base, and the base on the semiconductor layer. and an N or P type semiconductor layer of the opposite conductivity type.
Collector), N (emitter) P (base) N (collector), P (emitter) N (base) P'P (collector), P■ (emitter) N (base) P (collector)
A semiconductor device characterized by having a junction structure. 4. In claim 3, the intrinsic or substantially intrinsic semiconductor layer includes a semiconductor layer having an amorphous or semi-amorphous structure of silicon*t[E#0, and a P or N semiconductor layer on the semiconductor layer. 1. A semiconductor device, characterized in that a type semiconductor layer is a semiconductor having a microcrystalline or fibrous structure, or a non-single crystal semiconductor having a wider energy band than the semiconductor layer.