JPH03101267A - Thin film image sensor and its manufacture - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a thin film image sensor using an amorphous semiconductor and a method for manufacturing the same. Many of them have specific resistance and exhibit remarkable photoelectric properties (~
Photoelectric conversion element board In fields where a response speed roughly equivalent to that of the human sense is required, amorphous semiconductors are being widely used, taking advantage of their features such as ease of increasing the area and high resolution, and are still in the near future. Hydrogenated amorphous silicon (a-3i:
Despite the active development of thin-film image sensors using H) in the photoelectric conversion section, the reasons for this (Table 1) In addition to the characteristics of amorphous semiconductors mentioned above, The sandwich-type photodiode shown in Figure 3 is a typical example of a photoelectric conversion element using a-3i:H. Figure 3 (a) shows the plasma CVD method. According to a-3i:
H multiple layer 5a, a-8i by ion doping method: H
Although it is a top view showing only the nine layers 52(p) and the insulating layer 53, FIG. 3(b) is a cross-sectional view taken along the line X-X shown in FIG. As shown in FIG. 3(b), the manufacturing process of the diode element is as shown in FIG. 3(b).
A layer 52(n) and a layer 52(i) are deposited, a patterned fine insulating layer 53 is formed, and a contact window 54 is etched. :H 9 layers 52 (P)
After that, a common electrode 55 is formed to fabricate the first diode. As described above, an impurity layer 52 (p) which becomes a contact layer with the common electrode 55 is formed by an ion doping method. Impurity layer 52 which is a contact layer
(n) is a problem to be solved by the invention even though a method for forming the common electrode 55 by the conventional plasma CVD method was filed in Japanese Patent Application No. 1-45992 by one of the inventors.
The method of selectively forming the impurity layer 52(p) which becomes the contact layer with the Figure (a) is a cross-sectional view taken along the Y/-Ys line shown in Figure 3 (a). As shown in Figure 3 (a), as the degree of integration of elements increases, crosstalk between adjacent elements becomes a problem. Tekumu also a-8i: H52(n) and common electrode 55
In order to prevent short circuits with the An object of the present invention is to provide a thin film image sensor that is simpler and has higher performance than the conventional art, in which impurity layers can be insulated and separated between elements, and a method for manufacturing the same. In a configuration in which a plurality of photoelectric conversion elements each including at least a common electrode are arranged, a contact layer with each of the individual electrodes and a contact layer with each of the common electrodes are arranged. The present invention is a thin film image sensor in which the contact layers are separated by an i-type or nearly i-type amorphous semiconductor.The present invention has the above-described structure, so that both the contact layer with the individual electrodes and the contact layer with the common electrode are The contact layer is insulated and separated by an i-type or near-i-type amorphous semiconductor that is selectively formed and has high resistance.8 A method in which only the contact layer with the conventional individual electrode is selectively formed using an ion doping method. Embodiment Figure 1 shows a thin film image sensor according to the present invention. This is a process diagram showing the manufacturing method of the main parts.
a-8i of a): A top view with only the H layers 12(n) and 12(il) taken out; the same goes for Figure 1(d)
is a top view of only the a-3i:H multiple layer 14 in FIG. 1(C), and FIG. 1(f) is a top view of only the a-3i:H multiple layer 14 in FIG. 1(e). Below, we will explain how to manufacture the main parts of a thin film image sensor. First, we will start with an insulating substrate 10 made of Pyrex glass, quartz, etc.
A first i-type amorphous semiconductor 12 (i
A-3i: A mask 13 such as a resist is formed on the first i-type amorphous semiconductor 12 (it) to form a 0 layer 12 (n) of H. 212 as the second
A gas cylinder 201 is installed on the substrate table 211 of the plasma processing apparatus shown in the figure, and contains phosphine (PHs), phosphorus pentafluoride (PFI), arsine (As) as a gas containing group elements.
A mixed gas made by diluting a doping gas consisting of one type of pure gas such as Hs) with a diluent gas of helium or hydrogen in the gas cylinder 202 is supplied to the discharge chamber 203 through the gas introduction tube by adjusting the flow rate with the flow rate controller 213. Introduced from 204a
This mixed gas is discharged and decomposed by high frequency power supplied by the high frequency electrode 205, and the first electrode 20&
The DC voltage applied to the second electrode 207 pulls out ions in the highly excited plasma generated by discharge decomposition through the opening 208 and accelerates them. When helium is used as a diluent gas, ion damage caused by hydrogen ions, etc. is reduced (see Figure 1).
a), (b)). Then, a second i layer is deposited on the first layer 12 (il) and layer 12 (n) using the plasma processing apparatus, and then the p-type layer 1 is deposited using the above-mentioned ion doping method.
For example, diborane (B*H*), boron trifluoride (BFs), etc. may be used as a doping gas (as a gas containing a group element). In figure (c), the first layer 12 (il) and the second i
Combine the layers to form one layer 12(i) of a-3i:H,
5a-3i: When depositing one layer of H 12(i), trace amounts of elements such as P and B may be added in some cases (Fig. 1 (C)).
, (d)). Finally, a transparent common electrode 16 made of ITO, 5no2, etc. is formed (FIGS. 1(e) and 1(f)).

Although FIG. 4(b) is a cross-sectional view taken along the Y+-Y+ line in FIG. 1(f), it can be seen from FIG. 4(b) that the common electrode 16 and the individual electrodes 11 Contact layer a-3i: HI3(p) and aSi:
1Fif12 of a-3i:H in which all HI3(n) are selectively formed and the surroundings of each contact layer are all high resistance.
(i) Crosstalk between elements can be significantly reduced by insulation isolation, and there is no need to provide an insulation layer for element isolation (in this example, a transparent material such as ITO is used). A transparent electrode may be provided on an insulating substrate, and in either case, the optical signal to be detected is incident from the transparent electrode.
Force showing ip/ITO configuration <, nin/ITO instead of nip/ITO, p i p/ITo, p i
Effects of the Invention As is clear from the above explanation, the present invention provides a ζ slope in which both the contact layer with the individual electrodes and the contact layer with the common electrode are selective. In addition, the contact layer can be insulated and separated by an i-type or near-i-type amorphous semiconductor with high resistance.
Compared to the conventional method of selectively forming only the contact layer with individual electrodes using ion doping, crosstalk between elements can be significantly reduced, and there is no need for a new insulating film formation process for element isolation. Even if the process is simplified

[Brief explanation of drawings]

Claims (2)

[Claims] (1) A first impurity layer that is an amorphous semiconductor on a first electrode formed on a substrate, an i-type or near-i-type amorphous semiconductor, a second impurity layer that is an amorphous semiconductor, In a configuration in which a plurality of photoelectric conversion elements in which second electrodes are sequentially formed are arranged in a line, each of the first impurity layer and the second impurity layer of the adjacent photoelectric conversion elements is of the i-type or the i-type. A thin film image sensor characterized by having a structure separated by an amorphous semiconductor close to . (2) forming a lower electrode pattern on the substrate;
forming a first i-type or nearly i-type amorphous semiconductor layer on the lower electrode pattern; and forming a first i-type or nearly i-type amorphous semiconductor layer on the surface of the first i-type or nearly i-type amorphous semiconductor layer by an ion doping method. A first amorphous semiconductor layer having an impurity is selectively formed using a mask formed to separate the first i-type or near-i-type amorphous semiconductor layer, and a step of forming a first contact layer with the lower electrode pattern on an amorphous semiconductor layer of type or near i-type, and then a second amorphous semiconductor layer of type or near i-type on the substrate; forming a second amorphous semiconductor layer having impurities selectively on the surface of the second i-type or near-i-type amorphous semiconductor layer by an ion doping method; An upper electrode pattern is formed on the surface of a second i-type or nearly i-type amorphous semiconductor layer, and the second amorphous semiconductor layer is used as a second contact layer with the upper electrode pattern. A method for manufacturing a thin film image sensor comprising a process of