JPH0348464A - Manufacture of infrared detector - Google Patents

Abstract

PURPOSE:To easily manufacture an infrared detector by forming sections where infrared detecting elements are formed by removing parts of a crystal of a substance absorbing infrared rays formed on a substrate and removing compound semiconductor crystals grown on the crystal of the substance absorbing infrared rays after the compound semiconductor crystals are grown. CONSTITUTION:An Si crystal 2 is uniformly grown on one surface of a sapphire substrate 1 and a resist is applied to the surface 2a of the Si crystal 2. After applying the resist, the surface 2a is etched after masking, exposure, etc., and the Si crystal 2 is removed from parts 3 where infrared detecting elements are formed. Then Hg1-xCdxTe crystals 4 are grown on the surface of the substrate 1 on which the Si crystal 2 is formed. After forming the crystals 4, the crystals 4 grown on the Si crystal 2 are removed by polishing.

Description

[Detailed Description of the Invention] Summary Regarding a method for manufacturing an infrared detector using a compound semiconductor crystal, for the purpose of facilitating manufacturing, a compound semiconductor crystal that constitutes an infrared sensing element is formed on a substrate. In the method for manufacturing an infrared detector, a crystal of a substance that absorbs infrared rays is uniformly grown on one side of the substrate, and a part of the crystal of a substance that absorbs infrared rays formed on the substrate is removed, The infrared detecting element is formed into a portion, and after further elongating a compound semiconductor crystal on one side of the substrate, the compound semiconductor crystal formed on the crystal of the substance that absorbs infrared rays is removed. It doesn't matter.

INDUSTRIAL APPLICATION FIELD The present invention relates to a method of manufacturing an infrared detector using a compound semiconductor crystal.

Infrared detectors can detect the existence, shape, temperature, and composition of a target object without coming into contact with it, so it can be used for meteorological observation using satellites, crime prevention, disaster prevention, geological and geological surveys, and infrared thermography. It is used in many fields such as medical use. In order to increase the detection sensitivity of infrared detectors used in such fields, the viewing angle of the infrared rays that enter the detection element from the object to be detected is narrowed as much as possible to eliminate excess radiation coming from the background other than the object to be detected. It is desirable to eliminate lines. For this reason, an aperture plate (hereinafter simply referred to as an aperture) equipped with an infrared transmission window for determining the field of view that limits the viewing angle is generally placed in front of each detection element, and the infrared rays to be detected are detected through the transmission window. A configuration is adopted in which the light is made incident on the element. However, with the increase in the number of elements in infrared detectors, it is difficult to align each infrared transmitting window of the aperture with each detection element, and it is also difficult to fix the aperture due to its large size. As these drawbacks have become more apparent, there is a demand for an infrared detector that can adjust the viewing angle of incident infrared rays without using such an aperture.

BACKGROUND OF THE INVENTION FIG. 3 shows the configuration of a conventional infrared detector equipped with an averter. Reference numeral 6 denotes a substrate made of sapphire or the like, and a plurality of detection elements 7 are arranged on this substrate 6. 8
are metal bumps formed on both sides of the detection elements 7 in the arrangement direction and used as aperture mounting bases made of indium (In) or the like.

Reference numeral 9 denotes an aperture in which infrared transmitting windows 9a are formed at the same pitch as the pitch of the detecting elements 7, and the position of the aperture 9 is adjusted so that each infrared transmitting window 9a is at a position corresponding to the detecting element 7. For example, it is fixed to the metal bump 8 using an adhesive.

In the averter 9, a non-reflective film is formed on the infrared incident side of a substrate that transmits infrared rays, such as zinc sulfide (ZnS), and a non-reflective film is also formed on the infrared ray output side of this substrate, and the substrate and the non-reflective film are formed. Chromium (Cr), which does not transmit infrared rays, is placed between
), etc., and on the outer surface of the non-reflective film, a metal film made of aluminum (A The infrared transmitting window 9a is shaped like this. By making the area of the removed portion of the metal film corresponding to the upstream side in the infrared propagation direction slightly larger than the area of the removed portion of the metal film corresponding to the downstream side in the infrared propagation direction, the viewing angle is adjusted according to the area ratio. This is to prevent background light and the like coming from outside this viewing angle from entering the detection element 7.

Problems to be Solved by the Invention As described above, conventionally, the viewing angle of incident infrared rays has been limited by providing an aperture having an infrared transmission window at a position corresponding to the detection elements arranged on a substrate. However, as infrared detectors become multi-element, it becomes difficult to align each infrared transmitting window of the aperture with each detection element, and the aperture itself also becomes larger, making it difficult to fix it. The problem was that there were a lot of

The present invention has been made in view of these points, and an object of the present invention is to facilitate the manufacture of an infrared detector.

Means for Solving the Problem A crystal of a substance that absorbs infrared rays, such as 31 (silicon), is grown uniformly on one side of a substrate made of sapphire or the like, and a crystal of a substance that absorbs infrared rays is formed on the substrate. A portion is removed to form a portion that forms an infrared sensing element. Then, on one side of the substrate, H g l-X
After growing a compound semiconductor crystal such as C d X Te (cadmium mercury telluride), the compound semiconductor crystal grown on the crystal of the substance that absorbs infrared rays is removed. By manufacturing an infrared detector through such a process, the above-mentioned technical problem is solved.

Effect When an infrared detector is manufactured using the method of the present invention, the compound semiconductor crystal constituting the detection element will be formed in the valleys of the crystals of the substance that absorbs infrared rays. By adjusting the layer thickness of the crystal, it becomes possible to adjust the viewing angle of the infrared rays incident on the infrared sensing element (compound semiconductor crystal portion).

Therefore, since the crystalline layer of the material that absorbs infrared rays has the same effect as the aperture used in the past, the aperture is no longer necessary, the inconvenience caused by using an aperture can be solved, and its manufacture is simplified. can do.

Example Embodiments of the present invention will be described below based on the drawings.

FIGS. 1(A) to 1(D) are diagrams showing the manufacturing process of one embodiment of the present invention. First, a Si crystal 2 (layer thickness, for example, 50 to 60 μm) is grown uniformly on the - side of the sapphire substrate 1 by vapor phase or liquid phase epitaxial method (A
). A resist is applied to the surface 2a of this Si crystal 2, and etched by masking, exposure, etc., and the Si crystal 2 in the portion 3 that will become the infrared sensing element is removed (B). Hgl-. C
d. A Te crystal 4 is grown by a gas phase or liquid phase epitaxial method (C). Then, the Hg + -x C d) I Te crystal 4 grown on the Sl crystal 2 is removed by polishing (D). Incidentally, FIG. 2 shows a perspective view of the state after the steps up to this point have been completed.

Thereafter, an infrared detector is manufactured by forming electrodes and the like at predetermined positions (not shown).

According to this embodiment, the Hg, -XCdXTe crystal 4 that protects the infrared sensing element is formed in the valley of the S1 crystal 2, and the Si crystal 2 forms the infrared sensing element (Hg
+-. C d x T e crystal part) It is possible to limit the viewing angle of the incident infrared rays. And Figure 1 (
Hgl-X C on Si crystal 2 during polishing in D)
After removing the dll Te crystal 4, the Sl゛ crystal 2 is further removed.
It is possible to adjust the viewing angle by polishing or removing a portion of the screen and adjusting its height.

In this way, since the viewing angle of the incident infrared rays can be adjusted using the Si crystal 2, there is no need to provide an aperture as was conventionally used, and work such as adjusting the aperture position can be omitted, making it easier to manufacture. Man-hours can be reduced.

Effects of the Invention By manufacturing an infrared detector using the method of the present invention, there is no need to provide an aperture as conventionally used, and manufacturing is facilitated.

[Brief explanation of drawings]

1(A) to 1(D) are diagrams showing the manufacturing process of an embodiment of the present invention, FIG. 2 is a perspective view of the embodiment of the present invention, and FIG. 3 is an explanatory diagram of the prior art. ■...Sapphire substrate, 2...Si crystal, 4...Hg+-x cd, I Te crystal.

Claims (1)

[Claims] The compound semiconductor crystal (4) constituting the infrared sensing element is
In a method for manufacturing an infrared detector formed on a substrate (1), a crystal (2) of a substance that absorbs infrared rays is grown uniformly on one side of the substrate (1), and a crystal (2) formed on the substrate is formed. Crystals of substances that absorb infrared rays (2
) is removed as a portion for forming the infrared sensing element, and a compound semiconductor crystal (
4), the compound semiconductor crystal (4) formed on the crystal (2) of the substance that absorbs infrared rays is removed.