JPS5847874B2 - Manufacturing method of silicon target - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing an image pickup tube target having multiple PN junctions.

Image tube targets, e.g. vidicon targets, include:
A structure having a photoconductive film made of antimony trisulfide (Sb3S3) has generally been used, but this type of structure has limitations in its use due to drawbacks such as the burning phenomenon caused by strong light or electron beams.

Therefore, a silicon target as shown in FIG. 1 has since been used as a vidicon target having a structure that eliminates the drawbacks of the conventional example as described above.

Here, the silicon target is a semiconductor in which a transparent electrode 2 such as Nesa film is adhered to the inner surface of the face plate 1 of the image pickup tube, and a large number of PN junctions J are arranged in a mosaic shape on the transparent electrode 2. Due to the structure in which the layer 3 is provided, high sensitivity characteristics can be obtained without causing a burn-in phenomenon due to strong light or electron beams.

Then, the silicon target having the structure as described above is used as the second
As shown in the figure, an N-type semiconductor layer 3 with a thickness D that is easy to handle.
First, selective diffusion is performed on one surface 3a of the semiconductor layer 3 to simultaneously form a large number of independent island-like shallow P-type regions 4, and then the one surface 3a of the semiconductor layer 3 is The semiconductor layer 3 obtained by cutting the opposite side surface 3b to a desired thickness d was adhered onto the transparent electrode 2 to manufacture it.

By the way, in the silicon target having the structure described above, the loss of light reaching the PN junction J is determined by the thickness d of the semiconductor layer 3, and in order to obtain sufficient sensitivity, the above thickness d must be uniformly set to 20 μm. It is desirable that it be kept below this level.

Semiconductors with a uniform thickness of about 20 μm as described above are not only extremely difficult to manufacture, but also easily damaged during operations such as bonding them onto the face plate with adhesive, making it difficult to manufacture image pickup tube targets. This was a drawback in doing so.

Furthermore, the silicon target described above has the disadvantage that its PN junction deteriorates due to soft X-rays and secondary electrons generated inside the vidicon during operation (about several hundred hours).

Therefore, the present invention is a method for manufacturing a silicon target devised in view of the drawbacks of the conventional examples as described above, and its gist is to form a non-single crystal layer of a first conductivity type on a transparent substrate. After depositing and ion-implanting inert particles into the non-single crystal layer, the non-single-crystal layer is annealed, and a plurality of regions of a second conductivity type are formed within the ion-implanted region of the inert particles. This manufacturing method is characterized by the fact that it has individual shapes.

That is, in the present invention, first, in forming a photoconductive film, a highly uniform amorphous film of the first conductivity type is formed on the surface of the face plate using techniques such as vapor deposition, vapor phase growth, and sputtering. In this manufacturing method, a layer is deposited and a PN junction is formed on the first conductivity type layer.

Here, the characteristics of the PN junction formed on the non-single crystal layer are:
Compared to a single crystal, it is known that the lifetime of minority carriers in the crystal is about three orders of magnitude shorter due to its poor quality and the density of lattice defects, and the reverse current in the PN junction is about three orders of magnitude higher. There is.

Therefore, the present invention further provides that the crystal grains in a non-single crystal are minute single crystals, and that when ions are implanted into a single crystal, the quality deteriorates, but when it is annealed, it returns to a single crystal. By ion-implanting inert particles into the non-single crystal layer, a large number of lattice defects are generated in the non-single crystal layer to forcefully make the entire layer amorphous, and further, In this manufacturing method, the above region is annealed to convert it into a region consisting of larger single crystal grains than before, and a PN junction is formed in the above region.

Incidentally, the inert particles mentioned here consist of inert elements (for example, helium He, neon Ne, argon Ar, etc.), protons, hydrogen, etc., which do not adversely affect the operation of the semiconductor even if they are injected into the semiconductor. means particles.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to drawings showing one embodiment of the process.

In the present invention, the transparent substrate 10 has a thickness t of about 20 μm.

quartz glass or the like is used after its surface is chemically etched and cleaned.

Here, the above-mentioned chemical etching and cleaning are carried out in order to ensure the subsequent deposition of a non-single crystal layer of the first conductivity type.

[As shown in Figure 3 ■].

Then, on the surface of the transparent substrate 10, for example, a first conductivity type layer 11 having a low impurity concentration of N type is applied either through a transparent electrode or directly without using a transparent electrode as shown in the figure. It is deposited by vapor deposition, vapor phase growth, sputtering, etc. to a thickness t1 that can finally form a PN junction.

For example, about 0.1% monosilane (SiH4) gas and about 1xiO-(e~7)% arsenic hydride (A s
A thin film with a thickness t1 of about 5 to 10 μm is formed by performing epitaxial growth for about 2 to 3 hours at a growth temperature of around 900°C using Ha) gas as an impurity gas and argon (Ar) gas as a carrier gas. A polycrystalline N-type silicon layer is deposited as a non-monocrystalline layer 11 of a first conductivity type on the surface of a transparent substrate 10 [as shown in FIG. 3H].

]. According to such epitaxial growth, the thickness t1
A non-single crystal layer 11 of a first conductivity type having a uniform conductivity is placed on a transparent substrate 1.
It can be easily formed on the substrate.

Next, the surface 11 of the non-single crystal layer 11 of the first conductivity type is
From a, inert particles are ion-implanted to create lattice defects near the surface 11a of the non-single crystal layer 11, thereby forming a region of the non-single crystal layer 11 where a PN junction will eventually be formed. 11b is rendered non-quality.

For example, helium (He) ions are implanted into the thin polycrystalline N-type silicon layer obtained as described above at energies of 100 KeV and 200 eV.
The area from the surface to about 1.3 μm of the bottle is made into a non-quality area by striking the bottle twice (as shown in Figure 3 (■)).

]. Thereafter, by annealing the first conductivity type layer 11, the amorphous region 1lb becomes a single crystal grain with a larger grain size than before, and the surface of the first conductivity type layer 11 is A diffusion mask/insulating layer 12 is formed on 11a.

For example, an N-type silicon layer having an amorphous region as described above is annealed in dry oxygen (02) to make the above region into a single crystal, and at the same time, silicon dioxide is added to a region 1 μ4 degrees from the surface. (Sin2) layer is formed [shown in Figure 3 (■).

]. The region 1lb obtained in this manner is annealed after being made non-quality, so it is durable against soft X-rays and secondary electrons.

Further, a through hole is formed in the diffusion mask/insulating layer 12 by etching, and the impurity of the second conductivity type is diffused into the first conductivity type layer 11 through the through hole 13, and the second conductivity type impurity is diffused into the first conductivity type layer 11. A plurality of conductive regions 14 are formed to form a plurality of PN junctions.

For example, silicon dioxide (
6 μm × S i02 ) layer by photoetching.
A rectangular through hole with a diameter of 10μ is drilled.

Then, the holon (B) ion is introduced through the above-mentioned through hole.
With an energy of 0 KeV to 100 KeV, 1011 to 101
A plurality of regions with a uniform concentration of about 2i0n/a are obtained, and the implanted holon (B) ions are activated by annealing to form regions of the second conductivity type.

In this way, a PN junction J is formed by the above-mentioned first conductivity type layer and the second conductivity type region.

are arranged in a mosaic pattern to form a large number of them [Fig. 3 V
Shown below.

]. In order to prevent charge-up caused by electron beam scanning, a charge-up prevention film 15 made of a high-resistance material such as diantimony trisulfide (Sb2S3) with a thickness of about 0.1 M is coated on its surface. [As shown in Figure 3 (■).

]. In this way, the intended silicon target is obtained.

Further, FIG. 4 is a sectional view showing a silicon target for a single-tube color image pickup tube manufactured by the method of the present invention.

As shown in Figure 4, three
For each PN junction J, J2, J3, an index electrode 15' made of a secondary electron emitting material (for example, silver-cesium, antimony-cesium, etc.) is arranged on the charge-up prevention film 15, and a transparent An optical filter 16 that selectively passes red, green, and blue light is attached to the surface of the substrate 10 on which the PN junctions J1, J2, and J3 are not formed,
When the electron beam is scanned, the above index electrode 1
Secondary electrons from 5' are transferred to, for example, a mesh electrode (not shown).

) to obtain the index signal of the color signal, a single-tube color image pickup tube can be made using the silicon target made by the method of the present invention.

It goes without saying that the above index signal may be obtained from an electrode other than the mesh electrode.

As described above, according to the present invention, a photoconductive film is formed directly on a transparent substrate, and the photoconductive film is handled integrally with the transparent substrate during the manufacturing process. There is no need to adhere the formed photoconductive film to the substrate, and the risk of damage etc. can be significantly reduced, and the workability is improved, making it possible to manufacture efficiently.

Further, according to the present invention, since the photoconductive film is formed directly on the transparent substrate without forming it separately, it is possible to make the thickness sufficiently thin, and the above-mentioned improvement in sensitivity can be achieved. can be achieved.

Furthermore, according to the present invention, since a photoconductive film is used in which a PN junction is formed in the first conductivity type layer made of large single crystal grains obtained by once degrading the quality and then annealing, soft X-ray The durability against secondary electrons and secondary electrons can be improved.

[Brief explanation of drawings]

FIG. 1 is an enlarged sectional view of a silicon target. FIG. 2 is an enlarged cross-sectional view of one process showing a conventional method for manufacturing a silicon target. FIG. 3 is a manufacturing process diagram showing an embodiment of the method for manufacturing a silicon target according to the present invention, and FIG. 4 is an enlarged sectional view showing an embodiment of the silicon target manufactured by the method of the present invention.

Claims (1)

[Claims] 1 Depositing a non-single crystal layer of a first conductivity type on a transparent substrate,
After ion-implanting inert particles into the non-single crystal layer, the non-single-crystal layer is annealed to form a plurality of regions of the second conductivity type within the ion-implanted region of the inert particles. Characteristic silicon target manufacturing method.