JPS6221015Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a semiconductor device, and particularly to a semiconductor device that does not cause malfunction or characteristic deterioration due to the influence of high-energy charged particles such as radiation or cosmic rays.

In recent years, with the progress of space technology development, many semiconductor integrated circuits are being used in outer space, but these semiconductor integrated circuits are susceptible to malfunction or deterioration of characteristics due to radioactive particles, particularly high-energy charged particles such as alpha rays, that exist in outer space. There are things to do. Therefore, in order to prevent radiation from entering the semiconductor device,
Conventionally, a material that easily absorbs radiation was placed on the surface as a shielding plate to prevent radiation from reaching the semiconductor substrate.

However, with this method, a sufficient absorption effect cannot be expected because the coating thickness of the material that absorbs radiation is thin due to its structure.In addition, it is not effective against radiation that enters from the side or back surface of the semiconductor substrate, and it is There are drawbacks such as the fact that depending on the structure and the strict characteristics required, it may not be possible to provide a material that absorbs radiation on the surface.

SUMMARY OF THE INVENTION An object of the present invention is to provide a semiconductor device that can prevent malfunctions and characteristic deterioration caused by radiation, etc., in order to improve the conventional drawbacks.

In order to achieve the above object, a semiconductor device according to the present invention includes a semiconductor substrate and a permanent magnet provided near the semiconductor substrate, and the semiconductor device is arranged so that the lines of magnetic force caused by the permanent magnet intersect at a substantially perpendicular angle to the semiconductor substrate. A permanent magnet is arranged to reflect charged particles incident from the outside.

Therefore, it is possible to prevent the semiconductor device from malfunctioning or having its characteristics deteriorate due to high-energy charged particles incident on the semiconductor device.

Hereinafter, the semiconductor device according to the present invention will be described in more detail with reference to the drawings.

FIG. 1 shows an example of the state of magnetic lines of force in the vicinity of a permanent magnet. In the figure, 1 represents a permanent magnet, and such a magnetic field is called a magnetic mirror. Here, in general, charged particles that are incident at a certain magnetic field strength B ₀ at an angle α cm ² with respect to the lines of magnetic force will be reflected if the maximum magnetic field strength is Bm and satisfies sinα≧B ₀ /Bm. However, a necessary condition is that the radius of rotation of the charged particles at the magnetic field strength Bm is smaller than the radius of the permanent magnet.

For example, on Earth, there is a magnetic field of about 1 Gauss due to the earth's magnetic field, so B ₀ = 1 Gauss, and Bm =
If you use a 1000 Gauss permanent magnet, sinα
1000, that is, α≧0.057, and for the magnetic field lines
Charged particles that are incident at an angle greater than 0.057 degrees will be reflected.

FIG. 2 shows a cross-sectional view of a semiconductor device according to the present invention. In the figure, 1 represents a permanent magnet, 2 represents a semiconductor device, and 3 represents a semiconductor substrate. Permanent magnet 1 is the first
Assuming that the magnetized state is as shown in the figure, and the maximum magnetic field strength of the permanent magnet is 1000 Gauss, and the magnetic field strength near the back surface of the semiconductor substrate is 800 Gauss, charged particles incident from the top surface of the semiconductor device are Similar to the explanation in the figure, charged particles that are incident at an angle of 0.057 degrees or more with respect to the vertical line of the substrate will be reflected.
Charged particles incident from the back surface are aligned with the vertical line.
Charged particles that are incident at an angle of 0.072 degrees or more are reflected before reaching the back surface of the semiconductor substrate. Similar to FIG. 1, the radius of rotation of the charged particles must be smaller than the radius of the permanent magnet at the maximum magnetic field strength and the magnetic field strength on the back surface of the semiconductor substrate.

From the above explanation, charged particles that enter the semiconductor device, except for ultra-high energy charged particles and charged particles that enter almost perpendicular to the semiconductor device,
It will be reflected. Furthermore, charged particles that are incident almost vertically pass through the thickness of the semiconductor substrate as the shortest distance, so their influence on the semiconductor substrate is minimal and can be almost ignored.

As shown in Figure 2, a semiconductor device with a structure in which a permanent magnet is placed near the top of a semiconductor substrate and parallel to the substrate can cause malfunctions when radiation or high-energy charged particles enter the semiconductor substrate. Significantly improves the deterioration of properties.

3 and 4 show other embodiments of the present invention. 3 shows an embodiment in which the permanent magnets 3 are arranged in close contact with the upper surface of the semiconductor device 2, and FIG. 4 shows an embodiment in which the permanent magnets 3 are arranged on both the upper and lower surfaces of the semiconductor device 2. Both have a great effect of reflecting incident high-energy charged particles, and have the advantage that the permanent magnet can be arranged independently of the semiconductor device.

As is clear from the above description, the semiconductor device according to the present invention has a structure that makes it difficult for high-energy charged particles incident from the outside to enter the semiconductor substrate. This is especially effective in semiconductor devices used in outer space, where many charged particles of relatively low energy are incident.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the state of magnetic flux in the vicinity of a permanent magnet, FIG. 2 is a cross-sectional view of a semiconductor device according to the present invention, and FIGS. 3 and 4 are cross-sectional views of other embodiments of a semiconductor device according to the present invention. be. 1...Permanent magnet, 2...Semiconductor device, 3...Semiconductor substrate.

Claims (1)

[Scope of utility model registration request] 1. A semiconductor device comprising a semiconductor substrate and a permanent magnet provided near the semiconductor substrate, the permanent magnet being arranged so that lines of magnetic force caused by the permanent magnet intersect substantially perpendicularly to the semiconductor substrate.