JPS58125977A - charge transfer imaging device - 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 The invention relates to a solid-state device using a charge transfer device.Solid-state device rj, small and lightweight.

It is characterized by low power consumption and high reliability, and there is no worry about burn-in like in image pickup tubes, so it has been researched and developed in a wide range of fields in recent years.

FIG. 1 is a schematic diagram of one of the above-mentioned charge transfer imaging devices called an interline transfer method, in which a vertical shift register J l % I is emitted from a plurality of columns of charge transfer devices.
Q (!:h % A group of nine photoelectric conversion elements 11 arranged adjacent to one side of the vertical shift register, and a horizontal shift register 12 electrically coupled to one end of each vertical shift register.
t: A device consisting of a charge detection unit 11s13 provided at one end of horizontal shift register #12. FIG. 2 shows a coupling area between vertical shift register *10 and horizontal shift register 12 in the charge transfer imaging device shown in FIG. 14 is an enlarged view of V, the channel region 20 of the vertical shift register 10 has vertical charge transfer electrodes 21 and 22, and a vertical transtube gate electrode that controls the transfer of signal charges from the vertical shift register 10 to the horizontal shift register 12. 2
Covered by 3. Further, the channel region 24 of the horizontal shift register 12 has horizontal charge transfer electrodes 25, 26, 27°2.
Covered by 8%29. Roughly the same diagram.

The end region 3oy of the channel region 20 overlaps with a part of the horizontal charge transfer electrode 27, thereby forming a vertical one foot resist #l.
O and the horizontal shift register 12 are electrically coupled. Figure 8-3 is a cross section i on line 1-1 of the coupling area shown in Figure 2.
It is shown schematically. The above-mentioned vertical charge transfer electrodes 21. are formed on the main surface of the semiconductor substrate 31 with an insulating layer 32' interposed therebetween.
22. @Direct Trans Buddha Electrode 23. A horizontal charge transfer layer 1j27 is formed in the form IIt. Also, under each of the above electrodes there is a buried channel layer 331 of the conductivity type opposite to that of the substrate semiconductor, for example. ) 1 is formed, and a channel stop region 34 doped with an impurity of conductivity type opposite to that of the buried channel layer 33 is formed outside the channel region IIIvc. Further, the main surface of the semiconductor is shielded from light by, for example, a metal layer 35. In the same figure, area 3
'6 shows a region 30 in Figure 14h, which electrically couples a vertical shift register and a horizontal shift register, and shows a channel region of a 1-scale region 3'ld horizontal shift register - charge transfer imaging of such a structure. The operation of the device is as shown in FIG. 1, in which signal charges accumulated in the photoelectric conversion element group 11 according to the amount of incident light are read out to the vertical shift register group 10 corresponding to each frame period or field period of the video signal. Thereafter, the signals are sequentially transferred downward in parallel in the vertical shift register group 10 every 18 scanning periods (1B).

The signal charge transferred to the end of the vertical shift register group 10 is transferred to the horizontal shift register 12 every horizontal scanning period (IH) when the vertical transfer gate electrode 23 is turned on.
are injected in parallel. The ml1 charge sent to the horizontal shift register 12 is sequentially transferred in the horizontal direction while the signal charges are transferred from the ljl and M shift register group 10 in the next cycle, and is output externally as a video signal from the nh charge detection unit 13. Hetori 9 is taken out.

With conventional charge transfer imaging devices like this, high-brightness objects!
- A phenomenon that is unfavorable to the operation of the device has been observed, such as when the image is distorted laterally or in the opposite direction, or a false signal appears in front of the image. This phenomenon occurs when the charge transfer imaging device is applied to a single-chip color camera.

A certain %A also causes color shading. The above phenomenon is due to the structure of the coupling area of the vertical shift register and horizontal shift register shown in FIG. 2 or 3. Figure 4 1m1. (bJ, (c) is a turtle that schematically shows the potential distribution in each part of the cross-sectional view of the bonding region shown in Figure @3 to explain the above phenomenon, so Figure @4 (at, (b) is vertical). FIG. 4 shows the potential distribution at the time when the charge transfer electrodes 21 and 22 and the horizontal charge transfer electrode 27 are in the on state and the vertical transfer gate electrode 23 is in the off state. It shows the potential distribution at the time of the off-state!IK transition. Also, Fig. 5 is a diagram showing the relationship between the width of the channel region and the channel potential in this region. 4
The above phenomenon will be explained using the diagram and lN5 diagram. First, the fourth
rgJ(ml) The reason why the channel potential 9v of the region 36 shown in FIG. This is because it is smaller than the width WHK.In other words, the channel potential in the region with channel width W8 in Figure I!5 is slightly □, but the channel potential ψV in the channel width Wv sand i■ region is due to the narrow channel effect. Step 9 The above channel potential! is more pebble than □ - Therefore, in Fig. 4 (al), the channel region 37' of the horizontal shift register is
When a signal charge with a level smaller than V is transferred, the II charge does not enter the region 36, and efficient transfer is performed.However, as shown in the figure (bl), Kg
When the level of the No. I charge becomes so large as to exceed the potential difference ψyaw ψ7, a portion of the signal charge enters the region 36, significantly deteriorating the transfer efficiency of the horizontal shift register. This causes the image to flow in the horizontal direction when photographing a high-brightness object as described above. Furthermore, when the horizontal charge transfer electrode 27 is turned off, as shown in FIG. It is injected into the well 41. well 41
The false signal charge injected into fLk is again injected into the horizontal shift register at the timing when the vertical transfer gate electrode 23 turns on, and is the true signal charge n, To or 4.
! This causes the above-mentioned false signal on the horizontal line when photographing a high-brightness object, resulting in %A.

The object of the present invention is to provide a high-quality charge transfer imaging device for use in handbags, which eliminates the above-mentioned drawbacks.

According to the present invention, a plurality of vertical shift register groups each consisting of a charge transfer device formed on a conductive conductor of one conductivity type tv, a second photoelectric conversion element group arranged corresponding to the vertical shift register group, and a charge transfer horizontal shift register provided adjacent to one end of the vertical shift register group; and a charge transfer horizontal shift register provided by covering a channel region at the end of the vertical register group with a part of the horizontal charge transfer electrode of the horizontal register. a coupling part ξ between the shift register group and the horizontal shift register; a coupling part n provided at one end of the horizontal shift register;
Charge transfer imaging II! If the channel potential d under the horizontal charge transfer electrode pM becomes larger than the channel potential difference of the coupling portion compared to the charge transfer imaging ii*υ maximum signal level, then the seven vertical register groups exist. There is obtained a charge transfer imaging device characterized in that the impurity concentration of the semiconductor forming the coupling portion is greater than the impurity protection degree of the semiconductor forming the horizontal register.

Next, non-invention will be explained using drawings.

Il! FIG. 6 shows an embodiment of the charge transfer imaging device according to the invention, and the basic structure of the present invention is almost the same as that of the conventional example shown in FIG. 2 is a cross-sectional view of a coupling region 14 between the vertical shift register details 10 and the horizontal shift register 12 shown in FIG. 1,
This corresponds to Figure @3 of the conventional example. - In the same figure, i
T! The t of the same signal as in FIG. 3 indicates the same component. In the t1f3 diagram, the channel region and region 36 of the vertical shift register have the same conductivity type as the substrate 31.
110 - The channel potential of a π-inlaid channel formed on a semiconductor substrate with a high concentration is the same as that of a channel formed on a semiconductor substrate with a low concentration. Electrician 9 also becomes a small can. Therefore, for the same gate voltage, the channel potential of the buried channel formed on the semiconductor layer 38 in FIG. 6 is generally shallower than the channel potential of the channel region 37 of the horizontal register. For this reason, Fig. 4 (Fig. 4) shown in the conventional example)
The potential distribution corresponding to b (bls (c) is shown in Figure 7 (m
l * (bl h (c), 01 Unisu 4.lI!
The channel potential 9IH of the channel region 37 of the horizontal register in FIG. 7 is the same potential as in the conventional example.

The channel potential ψV of the region 36 is lower than that of Example 4 for the reason described above. Therefore, the channel potential difference -1 ψV has a value 4 larger than the conventional value. As a result, even if a large amount of signal charges are accumulated as shown in Tbl in FIG. 7, the accumulation of signal charges in the region 36, which is difficult to see in the conventional example, can be avoided. Therefore, even if the horizontal charge transfer electrode 27 is turned off, as shown in FIG. FIG. 8 shows another embodiment according to the present invention, in which a semiconductor substrate 42 having a conductivity type opposite to that of the substrate is formed.
M semiconductor 1941t - A non-imaging device lid is constructed on this semiconductor layer.
In the embodiment shown in the figure, the substrate 31 corresponds to the conductor R41, and the number of semiconductor layers 38 is one corresponding to the semiconductor layer 40! l! In the embodiment, the semiconductor layer 40 is set to have a higher concentration than the semiconductor $41.As a result, in the device according to the non-embodiment, the semiconductor layer 41 is assumed to be @s diagram υ group [31 @@6 diagram Shown in! i! You can think of it in the same way as the koji example.

As mentioned above, according to the invention, high brightness objects can be photographed using conventional charge transfer imaging devices! When the image is activated, the image 6 may flow horizontally, or a horizontal line-like false signal may appear in front of the image f'1. In the above description, for convenience, an N-channel device has been described, but it is clear that the gist of the invention is also applicable to a P-channel device.

[Brief explanation of drawings]

ll! FIG. 1 is a schematic diagram of an interline transfer type imaging device, and FIG. 2 is a schematic diagram of the coupling area of the vertical shift register and horizontal shift register in FIG. 1, showing a conventional example. Figure 3 is a cross-sectional view along line ``G'' in Figure 2. No. 41i!
II(al, 1b)-(cl is a schematic diagram of the potential distribution in Figure 3, gS diagram is a diagram showing the channel width dependence of channel potential, and all are the coupling regions of the vertical shift register and horizontal shift register in Figure 1. L in the present invention in a cross-sectional view of
6 structures are shown in Figure 7 (aJ, (b),
(c) u A schematic potential distribution diagram in FIG. 6, and FIG. 8 is a fist showing another embodiment according to the present invention, 1G is a vertical shift register group, 11 is a photoelectric conversion element group, 12 is a horizontal shift register, 13 is a charge detection section, 14 is a connection @r area of vertical shift register and horizontal shift register, 20H
Ii [channel region of shift register, 21.22 is vertical charge transfer electrode, 23 is vertical transfer gate l supervisor 2
4.37 is the channel area of the horizontal shift register, 25~
29 is a horizontal charge transfer electrode, 30.36 is covered with a part of the horizontal charge transfer electrode, and n7 is the end area of the vertical shift register;
31. 42 is a semiconductor substrate, 32 is an insulating layer, 33 is a buried channel layer, 34 is a frame channel stop region, 35 is a metal layer, 41t! A semiconductor layer 38.degree. 40 having a conductivity type opposite to that of the semiconductor substrate 42 is a higher concentration semiconductor layer having the same conductivity type as f'L31.41. Daidaijin Ben Onshi Nai Prize 1st Picture Horse! = Figure 7 (cL) (b] (C)

Claims (1)

[Claims] A charge transfer device formed on a semiconductor having one conductivity type and a group of vertical shift registers having multiple columns of FF14. a group of photoelectric conversion elements arranged corresponding to the vertical shift register group; a charge transfer horizontal shift register provided adjacent to one end of the +11111tvtiv-y register group; and a channel region at the end of the vertical register group. a coupling portion between the group of vertical shift registers and the horizontal shift register, which is provided so as to cover part of the horizontal charge transfer electrodes of the horizontal register; and a charge detection unit provided at one end of the horizontal shift register, wherein the difference between the channel potential under the horizontal charge transfer electrode and the channel potential of the coupling portion is the maximum of the charge transfer imaging device. Vh of the vertical shift register group is such that the impurity concentration of the semiconductor forming the coupling portion is greater than the impurity concentration of the semiconductor forming the horizontal register. A charge transfer imaging device that uses the sum of t4I molds.