JPS6066580A - Solid-state image pickup 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 FIELD OF INDUSTRIAL APPLICATION The present invention relates to solid state IFFIG i-floor equipment.

Conventional 1y++ 4V) structure and its problems In recent years, with the progress of semi-4F, semiconductor microfabrication technology, solid-state imaging devices have been manufactured using this semiconductor microfabrication technology, replacing the conventional full-fW tube. It is used as a substitute.

Hereinafter, the conventional solid state system 1'3 will be explained with reference to the drawings.

FIG. 1(a) shows a plan view of the main parts of a solid-state imaging device using a conventional interline transfer type CCD. Figure a31 (
b) shows a sectional view taken along lines A and A' in FIG. 1(a). Figure 1 (
In a) and (b), 1 is a photoelectric conversion element that converts an optical signal into signal electricity j, 2 is stored in the photoelectric conversion element 1,
11- a charge transfer gate that transfers the signal charge to the charge transfer element array 3; I, 'iJi' which accumulates and transfers the sent signal charge;
11 transfer element rows, 4 is the electric charge::j absorption region that absorbs unnecessary signal charges, and 5 is the excess 1 in photoelectric conversion element 1.
t-j > Excess of 1x transfer of J charge to charge absorption region 4'
1 liter load, 1 shi, 1 mg gate.

The operation of the solid-state 41V image device constructed as described above will be described below.

First, the photoelectric conversion element 1 converts the light to the photovoltaic signal 1b-III, and the converted signal charge passes through the charge transfer gate 2, '(
111 and is transferred to the charge transfer element array 3, the photoelectric conversion rate -r1 is accumulated. No. 15 accumulated in the photoelectric conversion element 1 passes through the charge transfer gate 2 to the charge transfer element array 3.
The excess signal charge is more than the maximum signal charge that can be accumulated in the photoelectric conversion element 1 (1 (-), the excess signal charge is more than the maximum signal charge that can be accumulated in the photoelectric conversion element The charge is transferred to the charge absorption region 4 through the charge transfer gate 5.

The signal charge accumulated in the photoelectric conversion element 1 is transferred to the charge transfer element array 3 through the charge transfer gate 2, and then transferred to the signal output section through the charge transfer element array 3.

Generally, -1 in the above solid-state imaging device, Table H of photoelectric conversion element 1
f+] The sensitivity is determined by the product, but the photoelectric conversion element 1 with
The surface area of charge transfer gate 2, charge transfer element array 3. Charge absorption region 4. It is limited back by the excess charge transfer gate 6.

However, in the above configuration, the charge transfer gate 2
Reducing the dimensions of the gate channel length will shorten the gate channel length, making punch-through more likely to occur at low voltages. Furthermore, reducing the dimensions of the charge transfer element array 3 reduces the transferable charge amount of the charge transfer element array 3, and in particular, the narrow channel effect tends to appear, and the transferable electric charge ij7 becomes smaller.
In addition to a decrease in jii-, the transfer effect is also significantly degraded, and reducing the size of the charge absorption region 4 leads to a decrease in the charge absorption capacity. In addition, reducing the ・J' method of the excess charge transfer gate 5 means that the charge transfer gates 2 and II
I can't make it smaller for some reasons. Koushi/This is the reason l-1
, in order to improve the sensitivity characteristics with the current q/S structure, 'tJ
N 4'+'□■'Li sending case 2. Charge transfer element row 3
．． Electricity Hf absorption area 4. It is not possible to reduce the dimensions of any one of the excess charge transfer gates 5 and increase the dimensions of 'J11' and the electric conversion element 10.

It had 17 drawbacks.

OBJECTS OF THE INVENTION In view of the above drawbacks, the present invention increases the dimensions of a photoelectric conversion element without causing deterioration of characteristics due to reduction in dimensions. The present invention provides a highly sensitive solid-state imaging device.

Structure of the Invention In order to achieve this object, in the solid-state imaging device of the present invention, the peripheral portion of the photoelectric conversion element has an inclined surface. In this configuration, the surface area of the solid-state imaging device is increased while keeping the light-receiving area constant, and everything other than the photoelectric conversion element is created on this inclined surface.
By increasing the area occupied by the photoelectric conversion element relative to the light-receiving area, a highly sensitive random operation can be obtained.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2(a) shows a plan view of a narrow portion of a solid-state imaging device according to an embodiment of the present invention. FIG. 2(b) shows a sectional view of A and A' in FIG. 2(-). In FIGS. 2(a) and (b), 1 is a photoelectric conversion element that converts an optical signal into a signal charge;
2' is a charge transfer gate that transfers the signal charge stored in the photoelectric conversion element 1 to the charge transfer element array 3, and 3 is a charge transfer gate that transfers the signal charge transferred from the charge transfer gate 2 while accumulating it. In the element array, 4 is a charge absorption region that absorbs unnecessary signal charges, and 6' is an excess charge transfer gate that transfers excess signal charge from the photoelectric conversion element 1 to the charge absorption region 4.

Here, charge transfer gate 2' and excess charge transfer gate 5'
is the peripheral part of the photoelectric conversion element 1, J゛11 part'+
1'.

It is.

A solid composed as above! The operation of the t141m device will be explained below.The optical signal is converted into a signal charge by the photoelectric conversion element 1, and the converted signal charge is created at a slope of 1n1. This accumulated signal charge is accumulated in the photoelectric conversion element 1 until it is transferred to the charge transfer element array 3 through the charge transfer gate 2'.
The charge can be stored in the photoelectric conversion element 1 before being transferred to the charge transfer element array 3 through the charge transfer element array 3. 1->Hb: If the ratio is 6:1 or more, the maximum signal load that can be stored in this photoelectric conversion element 1 is exceeded.
1 +11i P (2 made excess charge transfer gate 5'
The electricity is transferred to the electric i:j absorption region 4 through .

i1-1 tun i accumulated in the photoelectric conversion element 1:・“jQ
J4, (d traces the charge transfer gate 2 formed on the surface 'I:5Φ)], is transferred to the transmission element array 3, and then transferred to the signal output section through the charge transfer element array 3.

As described above, according to this embodiment, an inclined surface is formed around the photoelectric conversion element r-1, and charge transfer gates 1 and 2 are formed on this inclined surface.
', and by creating an excess charge transfer gate 5', the charge transfer gate 2 causes punch-through at low voltage.
In addition, the amount of charge that can be transferred is reduced without increasing the amount of excess charge transfer gate 5, and the narrow channel effect is particularly likely to occur, which not only reduces the amount of charge that can be transferred but also causes a significant deterioration of transfer efficiency. To provide a high-quality imaging confectionery in which the dimensions of a photoelectric conversion element 1 are increased without reducing the dimensions of a charge transfer element array 3, which would cause a decrease, and without reducing the dimensions of a charge absorption region 4, which would cause a decrease in charge absorption capacity. be able to.

In the present invention, the charge transfer gate 2' and the excess charge transfer gate 6' are provided on the inclined surface of the peripheral part of the photoelectric conversion element 1, but the gates provided on the inclined surface of the peripheral part of the photoelectric conversion element 1 are It may be the transfer element array 3 and the charge absorption region 4.

Effects of the Invention As described above, the present invention creates an inclined surface at the periphery of the photoelectric conversion element, and by utilizing this inclined surface, it is possible to make the photoelectric conversion element as a large, 6-sensitivity imager. It is possible, and its practical effects are similar to that of a dog. cormorant

[Brief explanation of the drawing]

Figure 1 (a) +d Conventional interline transfer method CC
A plan view of the main parts of a solid-state imaging device using D, FIG. 1(b)
is a cross-sectional view of A and A' in FIG. 1(a), and FIG.
Figure 2 (b) is a sectional view of A and A' in Figure 2 (-).
-11...Photoelectric conversion element array, 2'...Charge transfer gate, 3...Charge transfer element array, 4...Charge absorption region, 5'...Excess charge transfer gate. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2

Claims (2)

[Claims] (1) l'= photoelectric conversion element arrays arranged in a matrix on a conductor substrate, readout means for reading out signal charges accumulated in the photoelectric conversion elements, and the semiconductor substrate on the side of the photoelectric conversion element arrays. IIJIIj inclined with respect to the principal plane of;
- A solid-state imaging device comprising: -1 part. (2) A solid-state imaging device according to claim g1, characterized in that a gate electrode is formed on the inclined portion.