JPS58137250A - Solid-state image pickup device - Google Patents

Abstract

PURPOSE:To improve the resolving power of a picture regenerated by disposing transfer gates on both sides of a charge transfer section, providing the outsides of the transfer gates with light-receiving element rows consisting of two series and flowing charges from light-receiving elements into different cells of the transfer section. CONSTITUTION:The charge transfer section 24 is formed to a meandering channel shape, and the longitudinal rows of the light-receiving elements composed of two series are arranged on both sides. The transfer gates 2a, 2b connected to terminals 7a, 7b are disposed to the upper section of the charge transfer section. Charges from each light-receiving element 1 are flowed into different cells 26 or 26' or 27 or 27' of the charge transfer section 24. According to such constitution, the numbers of several picture element in a light-receiving surface 50 are increased without changing a light-receiving area, and the revolving power of the picture regenerated can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Summary of the Invention The present invention relates to a solid-state imaging device, and more specifically to the structure of a so-called interfin transfer type imaging device.

(To) Technical Background In recent years, with the remarkable development of semiconductor manufacturing technology, solid-state imaging devices have tended to become increasingly highly integrated. Based on the requirements.

Main) Conventional technology and problems Figure 1 shows the conventional interfin transfer type (hereinafter referred to as I
1 is a plan view showing the structure of a solid-state imaging device (abbreviated as T-type). In the figure, reference numeral 50 denotes a light-receiving surface, in which adjacent ropes l lined up in the vertical direction are separated from each other on three sides by a charge weir 21 indicated by a broken line, and photoelectric conversion is carried out in the pixels l. The charge generated at terminal 5 is applied to voltage VT
When is added, a channel is created just below the transfer gate 2, so that it flows through the transfer gate 2 into the unit Sefi/8 in the vertical direction C0DIO. and the longitudinal CCD10
If the charge is transferred in the vertical direction as shown by the arrow opening, the charge is introduced into the unit cell in the horizontal CCD 20 as shown by the arrow C, and is transferred in the two directions of the arrow. detected by the detection amplifier 4 and sent to the output terminal 18.
is extracted as a time-series signal.

However, in such an IT-type solid-state imaging device,
Since the columns of light-receiving elements 1 are arranged alternately with longitudinal charge transfer devices (hereinafter abbreviated as COD) 8, the actual light-receiving area becomes considerably smaller than the light-receiving surface 50. Furthermore, for convenience, although not shown, C0DIO and C
Multiple busbars are placed on the top surface of 0DIO to supply transfer voltage to each transfer electrode, but recently, in order to improve resolution, the width of COD has been reduced to be as small as the area occupied by the photodetector. For example, there is a trend to increase the number of pixels from 50 pixels to 100 or 150 pixels. In this case, it becomes necessary to make the width of the COD smaller and smaller, but the width of the COD in the vertical direction
If the width of O is less than 20 μm, for example, the transfer efficiency will drop significantly.

Furthermore, since the width of the generatrix cannot be made less than a predetermined value for manufacturing purposes, there is a drawback that it becomes even more difficult to increase the integration density of an imaging device having such a conventional structure.

4. Purpose of the Invention In view of the above-mentioned conventional drawbacks, the present invention provides an IT that can be highly integrated in order to increase the number f of each pixel in the light receiving surface 50 and improve the resolution of reproduced images without changing the light receiving area. (e) Structure of the Invention According to the present invention, it is an object of the present invention to provide a photoelectric conversion section comprising a plurality of light receiving element arrays, and a method for converting charges in the photoelectric conversion section. In a configuration mainly consisting of a transfer gate that transfers and a charge transfer section that receives and transfers charges via the transfer gate, transfer gates are arranged on both sides of the charge transfer section, and A solid-state imaging device characterized in that a light-receiving element row of a photoelectric conversion section consisting of two series is provided on the outside, and the charge from each of the light-receiving elements flows into different seven points of the charge transfer section. This is achieved by providing

(Embodiments of the Invention Below, the embodiments of the present invention will be described in detail with reference to the drawings. Fig. 2 is a plan view showing the main structure of the T1n solid-state imaging device casing according to the present invention, which is equivalent to Fig. 1. The vertical CCD as a part is a so-called meander channel /I/!!l!, and most of the parts on both sides are photoelectric conversion parts, that is, light receiving parts 11a.
, as well as cell lvl in llb.

It is indicated by diagonal lines and is surrounded by a charge weir 21, and is structured as if it is sandwiched between two columns of light-receiving elements I.

A terminal 7a is provided above the thick charge weir fl'' that sandwiches the longitudinal direction ccD of the meander channel/L'5.

The transfer game connected to 7b) 2a, 21) is installed, but the above terminal? a, 7b, Figure 3)
When voltage φTG is applied during the period from time t1 to time t2 shown in FIG. A channel arises.

In this case, the transfer voltage φl is applied to the terminal 8a as shown in FIG.
) As shown in the above, if a high level is applied during the period of ti-tg, the potential surface of the 0CCD set/l/, 26 directly below the transfer electrode 28a decreases, and the potential well (hereinafter simply referred to as well) is lowered. occurs, the sensor in the light receiving section 11b
The charges generated by photoelectric conversion in l/1 pass through the channel to the CCD cell IV8 as shown by arrow A.
By the way, since the hatched part 26' of the cell g6 above is doped with impurities of the same conductivity type as the KFi semiconductor substrate, the well in the part 26' is not shaded. The well has also become shallower. Therefore, the charge a1 flowing into the above-mentioned non-hatched area flows back into the hatched area.

In this case, as shown in FIG. 8 (to), the electrode gsaVc is supplied with the voltage φl from the terminal 8b and maintains a high level μ at the end time tt-tz.
There is also a well in OD7A/2F.
The wells in the shaded area 27' of 27 are shallow, and the wells in the non-shaded area are deep.

Therefore, the charge photoelectrically converted in tIvl shown in the middle of the light receiving part 11a is transferred to the transfer gate ()2 connected to the terminal 7a.
Since the aK voltage φTG is applied and a channel is also generated directly under the charge path 22a, the above-mentioned C
At the same time as the charge flowing into the CD cell A/26, the t charge ti charge a path 22a in the center 7yl of the light receiving section 11a
It flows into CCD-klv27 through t and becomes O. In this case as well, the well in the 9th part 27' shown by the diagonal line is shallower than the well in the part without the diagonal line, so the above-mentioned reverse flow of charge does not occur. This is no different from the charge backflow prevention measure in COD.

Then, by the same process as above, the electrode 28 of the CCD [24]
The above t;-tg is also applied to the bottom 7μ directly below a.

In the meantime, there is a danger that charge will flow from the lowest stage SEA/l of the light receiving section 111) to the direction of the arrow A, and the voltage φl applied to the electrode 28& will be as shown in Fig. 8 (
As shown in FIG. 8(0), the voltage φ applied to the electrode 28b from the terminal 8b remains at a high level even from time t8 to t4, and the voltage φ applied from the terminal 8b to the electrode 28b increases from t8 to t4 in FIG. 8(0). When it becomes low, 0CDi directly below the electrode 28b
Since all the 7μ wells to the right of lS24 disappear,
The charge existing in the 7 μ 27 flows into the Sefi/14 on the left side of the COD section 24 as shown by the arrow H and becomes [Stock]. However, in this case, as mentioned above, C0DilS2
Since the wells of the cell on the right side of 4 have all disappeared, the charge of . does not move and just stays in the same position. After reaching a good state, the voltage φ
1. φ2 is the above-mentioned charge@
, (Q, @ is first transferred to each cell on the right side of the COD section 24 as shown by the arrow, and then transferred to each cell on the lower left side, where the serpentine transfer of charge begins. The above CCD 111g4 is arranged in plural lines in the light receiving surface 60 shown in FIG. 1. However, since the CCD section shown in FIG. 2 is of a so-called meander channel type, the transfer voltage is The busbars for sending are the transfer electrodes 28a, 28
It is not necessary to arrange it on the terminal b, and it is sufficient to simply connect one end of each of the electrodes to the terminals sa and sb as shown in the figure. For this reason, the width of the CCD 111g4 is no longer limited by the width of the generatrix, and therefore the width of each of the CCD portions 24 shown as 24a, 241) can be narrowed to, for example, 15 μm.

Furthermore, unlike the configuration shown in Figure 1, the configuration shown in Figure 2 is one in which two light-receiving element rows are connected to one vertical CCD section, so such a configuration was not adopted. Ba,
Even if the light-receiving area is the same, the number of pixels and the number of vertical CODs arranged in the area can be increased compared to the conventional one, and therefore, it is possible to further increase the integration of the imaging device. Since this only increases the number of lateral COD cells, there is no need to increase the size of the lateral CCD 20.

In the above embodiment, the vertical COD has been described as having a meander channel structure, but even if the vertical COD does not have a meander channel type, the above-mentioned high integration is possible to some extent. If this is depicted as a modified example, the configuration will be as shown in FIG. 4. However, the symbols in this figure are the same as the equivalent parts in FIG.

Although the vertical direction CCt110 in FIG. 4 is not a meandering channel type, it still has one vertical direction C0DI.
Because the rows of light-receiving elements L that appear from two rows are arranged adjacent to O, the light-receiving area can be avoided without increasing the vertical and horizontal COD and the light-receiving elements arranged on the light-receiving area. The number can be increased considerably, making it possible to achieve high integration.

Effects of the Invention As explained in detail above, the IT-type body gymnastics imaging device of the present invention can be integrated at a higher density than ever before with the same light-receiving area, so it has great practical effects. You can expect it.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the structure of a conventional ITT solid-state imaging device, FIG. 2 is a diagram showing the main structure of an ITT solid-state imaging device according to the present invention, and FIG. 8 shows the operation of the imaging device shown in FIG. In the timing diagram shown in FIG. 4, which is a diagram showing a modified embodiment of the present invention, l is a light receiving element, 2a, 2
1) is a transfer gate, 7a, 7b, 8a, 8b are terminals,
lla, 111) is a light receiving part, 1i11.21' is a charge weir, 22a, Hl) is a charge path, and 24 is a vertical CCD.
The parts are shown respectively. (-” To 2 to 6 6 ()-

Claims (1)

[Claims] In a configuration mainly consisting of a photoelectric conversion section consisting of a plurality of light-receiving element arrays, a transfer gate that transfers charges in the photoelectric conversion section, and a charge transfer section that receives and transfers charges via the transfer gate. , transfer gates are arranged on both sides of the charge transfer section, and furthermore, a light receiving element row of two series of photoelectric conversion sections is provided outside the transfer gate, and the charge from each of the light receiving elements is transferred to the charge transfer section. A solid-state imaging device characterized in that it is configured to allow flow into a different cell.