JPS6014464A - Infrared ray image pickup device - Google Patents

Abstract

PURPOSE:To obtain a solid-state image-pickup device with which a measurement of absolute temperature can be performed easily by a method wherein two or more kinds of narrow band-pass filters, having different transmissive wavelength regions on the infrared ray incidence surface of a photoelectric conversion part, are provided. CONSTITUTION:Infrared rays are made to incident from a metal side electrode of Schottky junction. Filters 13, 14 and 15 are narrow band-pass filters having different band-passes respectively. As generally known, the filters are formed into mosaic form or stripe form using a dielectric multilayer film by performing a sputtering method, a vapordeposition method and the like. The signal charge obtained by performing a photoelectric conversion is conveyed to a vertical shift resistor 1 through a transfer transistor 3, it is transferred in the lower direction inside a vertical shift resistor 1, a signal charge is moved to a horizontal shift resistor 4, it is transferred in the left direction inside the horizontal shift resistor 4, and the electric charge is read out from an output part 5. Pertaining to photoelectric conversion, the absolute temperature and the emissive power of a substance are obtained from the signal of the three adjoining photoelectric conversion parts 2-1, 2-2 and 2-3, using the formula of the signal charge of the infrared rays passed through the filters 13, 14 and 15.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an infrared detector that performs photoelectric conversion of infrared light.
Arranged in two dimensions or two dimensions, each infrared IYllJ
! This invention relates to an infrared imaging device equipped with a scanning mechanism that sequentially reads signal charges from a detector.

In recent years, the development of solid-state imaging devices has progressed rapidly, and devices that can withstand practical use are being developed one after another. F, a solid-state imaging device with a large number of picture elements that has high resolution even in the infrared field
M light is being advanced, and infrared imaging devices that use a Schottky junction of platinum silicide and p-type silicon in the detection section in particular can be manufactured using a silicon wafer process, making them suitable for high integration. , those with a large number of picture primes have been developed.

Figure 1 shows the first cause of an infrared imaging device when a Schottky junction is used as an infrared emitting element, and Figure 2 shows the first cause.
■-! It is a sectional view taken along I line.

2 in Figure 1, 1 is a vertical soft register, 2 is an electric converter for detecting infrared rays, and 3 is the original 'rCL converter 2.
4 is a horizontal shift register, and 5 is an output section.

In FIG. 2, 6 is a p-type silicon substrate, 1 is a silicon oxide film, 8 is a gate electrode of a vertical shift lens, 9 is a gate electrode of a transfer transistor, and 10 is a platinum silicide of a Schottky junction that performs infrared photoelectric conversion. ,1
1 is an n-type region that becomes the source of the transfer transistor, and 12 is an n-type region that forms a Schottky junction card ring.
m area.

Next, the operation of such an infrared imaging device will be explained. A Schottky junction of p-type silicon and platinum silicide has a Schottky junction barrier height of approximately 0.27 e'V and is used for atmospheric windows in the 3-ba1 m range. When infrared light is incident on a Schottky junction, electron and hole pairs are generated, and among these, the hole with an energy of 7 that exceeds the Schottky junction exceeds the Schottky burry 1''
Cp type silicon substrate 6VC is implanted. As a result, signal charges (electrons) are accumulated in the platinum sisoside 1u of the Schottky junction. This signal charge is transferred to the transfer transistor 3'rONj KJ:';l,n! Territory area 1y
a'' to the vertical shift register 1. The signal charges read to the vertical shift register 1 are sequentially transferred downward within the vertical shift register 1 and transferred to the horizontal shift register 4.To the horizontal shift register 4 The transferred signals are sequentially transferred to the left in Fig. 1 and read out from the output section 5.
The photoelectric conversion mechanism will be described in detail next.

Photoelectric conversion in a Schottky junction follows the following equation, also known as the Fowl, er equation.

In the above equation (11), η is the efficiency of l, l) is the blank foot μ, λ is the wavelength of infrared rays, ψmB is the barrier sieve of the Schottky junction, co is the shape of the photoelectric conversion unit 2, There is a constant 't' determined by the configuration etc., and C is the speed of light.

Further, if the source of infrared rays is a black body, the spectral brightness Bλ is given by the blank equation (2) below.

Here, C,, C, is a constant and T is the absolute temperature.

No. +11. From the formula +21, the signal charge nB can be calculated as follows.

Here λ. , λ1 are the upper and lower limits of the wavelength of infrared light incident on the shot 4-junction. lFor example, when infrared light is incident from the silicon side of a Schottky junction, λ. is determined from the bandgap of silicon and is λ. =1.1μm
, λ is determined from the Schottky barrier height and is 9.9 m.
When g-0,27eV, λ1=4.6 μm. λ
. By appropriately selecting the value of and λ1, it is possible to obtain the absolute temperature T from the signal charge n using J:9 and equation (3). However, objects that actually exist are not black bodies, and have a unique radioactivity ε depending on the material surface condition of the object.

Therefore, the spectral brightness is obtained by multiplying Bλ in equation (2) by radiation ε, and equation (3) is also changed as follows.

Absolute temperature T of the object from signal charge n8? To find it, you need to know the value of radioactivity 6 and make corrections.

Further, since the radiation activity ε differs depending on the surface condition, when the output of the infrared image sensor is displayed, for example, in brightness, high brightness does not necessarily correspond to high temperature.

This invention was made to eliminate the drawbacks of the conventional infrared imaging device as described above, and includes two or more types of narrowband filters with different transmission wavelength ranges on the infrared light incident surface of the photoelectric conversion section. The object of the present invention is to provide a solid-state imaging device a that can easily measure absolute temperature.

This invention will be explained below.

Fig. 3 shows an embodiment of the present invention.
The figure is a sectional view taken along the line ■-■ in FIG. 3.

This embodiment is an example in which infrared tC is incident from the metal side electrode of a Schottky junction.

In FIGS. 3 and 4, 13, 14, and 15 are narrow band filters having different bands, respectively. The filter is good (
As is known, r) the dielectric multilayer film may be formed in a mosaic or stripe shape by a spackle method, a vapor deposition method, or the like. Others ij - Same as FIGS. 1 and 2.

Next, the operation will be explained. The signal charge obtained by photoelectric conversion is handled by the transfer transistor 3 in the same way as before.
ygn and transfer it to the vertical shift register 1, transfer it to the Z downward direction in the vertical shift register 1, transfer the signal charge to the horizontal shift register 4, transfer it to the left in the horizontal shift register 4 in Fig. 3, and transfer the charge to the left. is output from the output section 5J-9iffl.

For photoelectric conversion, filters 13.14. The (iQ) charge due to the infrared light that has passed through the 15 waves is given by Equation (4). Here, Δλ is the half-width of the center-spread λ reno filter. Using this Equation (5), the third The absolute temperature T and radiation ε of the object can be obtained from the signals of the three instantaneous 9/5 element converters 2-1, 2-2, 2-3 shown in the figure.

In the above embodiment, the Schottky junction metal (+1
Although the filters 13 to 15 are formed on the electrode 11, when infrared light is incident from the silicon surface, it is sufficient to form the filters on the silicon surface. Furthermore, although the above embodiment is a case where the Schottky junction 7 is used for photoelectric conversion, when a semiconductor such as HgCdTe or InSb is used for the photoelectric conversion section 2, an extrinsic type silicon that utilizes the impurity level in Si may be used. It goes without saying that WI can be similarly achieved in the case of the photoelectric conversion section 2, etc.

As explained in detail above, the present invention allows the infrared light to enter the photoelectric conversion section after passing through the filter, and the absolute temperature T of the object can be easily determined. , the absolute temperature distribution can be obtained. In addition, by configuring the filter on the chip, the combined density of the photoelectric conversion section and the filter can be improved, and reliability can be improved.Furthermore, the number of inspection points can be reduced, making it possible to perform infrared imaging at low cost. It has excellent advantages such as being able to provide element Z.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram of a conventional infrared imaging device, and Figure 2 is a diagram of a conventional infrared imaging device.
3 is a block diagram showing a seventh embodiment of an infrared imaging device according to the present invention, and FIG. 4 is a sectional view taken along PJ-IV in FIG. 3. In the figure, 1 is a vertical shift register, 2 is a photoelectric conversion section, 3 is a transfer transistor, 4ii is a horizontal shift register, 5 is an output section, 6 is a p-oxide silicon substrate, I is a silicon oxide film, 8 and 9 are gate electrodes, 10 is platinum silicide,
11 and 12 are n-type regions, and 13 to 15 are filters. Note that the numerals in the drawings indicate the same or corresponding parts. Agent: Masuo Oiwa (2 others) %”: 1 Figure 3 Figure 4 Amendment to figure procedure (voluntary) 1. Indication of the case Japanese Patent Application No. 122924/1982 2. Title of the invention Infrared imaging device 3. Amendment Person 4, Agent 5, Detailed description of the invention in the specification subject to amendment 4[y1 6, Contents of amendment (1) "Platinum silicide" in line 2 on page 3 of the specification is changed to "platinum silicide IOJ" to correct. (2) Similarly, on page 8, line 10, "investigation location" is corrected to "adjustment location". I"2

Claims (1)

[Claims] In an infrared imaging device including an infrared photoelectric conversion section two-dimensionally arranged on a semiconductor substrate, and a mechanism for sequentially reading out signal charges from the photoelectric conversion section, an infrared light incident side of the photoelectric conversion section has a transmission wavelength range. An infrared imaging device characterized by forming a plurality of different types of infrared a-band pass type filters.