KR930007094B1 - Method of making and using selective conductive regions in diamond layers - Google Patents

Abstract

No content.

Description

Method for forming conductive region in diamond lattice substrate and electrical apparatus manufactured by this method

1 is a cross-sectional view of an illuminated diamond lattice substrate.

2 is an enlarged view of the diamond lattice substrate of FIG.

3 is a cross-sectional view of an integrated circuit having a diamond package layer having conductive terminals.

4 is a cross-sectional view of a capacitor and a resistor formed in the diamond layer.

5 is a partially cutaway perspective view of a circuit board incorporating the principles of the present invention.

* Explanation of symbols for main parts of the drawings

20: integrated circuit 22: collector area

24: base area 26: emitter area

30,32 insulation layer 34 graphite region

42,44 plate 46: contact area

50: circuit board 52, 56: conductive pattern

54: conductive layer

The present invention relates to a method for forming a conductive region in a non-conductive material, and to an electrical device manufactured by the method, and more particularly, to a method for forming a conductive region on a diamond lattice substrate and an electrical device manufactured by the method. .

The inventors of the present invention have intensively studied the impact of impacting charged particles with high energy on diamonds. As a result of this study, high-energy particles for making quality marks on gems, especially diamonds US Patent No. 4,200,506 has been obtained regarding the use of beams. This patent discloses a very localized change in the optical properties of the diode by the introduction of a very thin layer of radiation damaging lattice.

With the continued growth of diamond films, the inventors of the present invention have become deeply interested in the use of high energy particle beam impacts to create conductive graphite regions in diamonds, which applications As well as devices, they can be widely used in semiconductor devices, integrated circuits, small electronic devices and circuit boards.

The high thermal conductivity as well as the diamond's resistivity to radiation make it possible to make ideal packages, insulating layers and heat sinks compared to other materials already used in semiconductors. In the orient, the use of a diamond package enables optical communication into the package.

Preferred techniques for forming high conductive regions in insulating materials are disclosed in US Pat. No. 4,511,455 to Forrest et al. Low-resistance materials are obtained by irradiating the carbon-containing material with particles having at least one atomic weight.

The treatment process involves chemical decay of the carbon-containing compound by radiation decomposition caused by the impact of charged particles. This technique produces columnar conductive amorphous carbon.

However, the Forest patent can be applied to a general carbon-containing material, but there is no mention of the nature of the diamond mode, the use in the electronics industry, or the technique of forming the conductive region under the diamond surface.

Accordingly, an object of the present invention is to provide a method for selectively forming a conductive region in a diamond substrate.

Another object of the present invention is to provide a method for forming a conductive region in a diamond substrate under the substrate surface.

Yet another object of the present invention is to provide a method for forming a conductive region in a diamond substrate that can be used under high temperature and high radioactive atmospheres.

These and other objects of the present invention are directed to conducting graphite in a plane perpendicular to the irradiation axis by irradiating the substrate of the diamond lattice with high energy charged particles having sufficient flux and energy level for a sufficient period of time. By an irreversible transformation into. Cooling while irradiating the substrate to confine the graphite to one area of the plane at a predetermined depth within the substrate. Then, irradiation is performed for several minutes to several hours at an energy level of 100 KeV to 4MeV. The charged particles are preferably single energy protons, but are selected from the group of protons, heavy protons or alpha particles.

The cooling temperature is in the range from 4 ° K to room temperature.

By the above processing, it is possible to contact or interconnect on an integrated circuit device or a circuit board. In the same way, the above processing process can form the plates and the terminals of the condenser on the electronic device. In addition, the treatment process can penetrate the insulating diamond layer or form resistance and other conductive elements in the layer.

Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention which has been described based on the accompanying drawings.

As shown in FIG. 1, it is shown that the diamond lattice substrate is impacted by the proton beam 2.

As protons enter the crystal through surface 4 these protons lose energy through ionization. The crystal lattice is not heated strongly in the region 6 of the crystal and no change occurs. However, at the end of the path of the proton particles, the change occurs in a very small localized region of the crystal lattice, as shown by region 8. The remainder of the decision is not changed and is shown as region 10.

Figure 2 shows the individual displacement spikes, which are changes that occur in small localized regions due to the strong heat generated when the proton particles are stopped.

As shown, each spike is formed into an area of about 0.01 microns in diameter, containing about 10 ° atoms. The area in which the displacement spikes evolve consists of permanent changes that can be detected when inspected using a microscope.

Natural diamond crystals cause permanent changes in the crystal at the point where the particles stop when irradiated with a single energy proton by a van de Graaff accelerator. If particle energy in the range of about 0.1 MeV to about 4 MeV is used, the crystal surface is not damaged by sputtering, and no nuclear reaction occurs to diamond radiation after the treatment is completed. Protons impacting the diamond are in a very limited and highly predictable manner, stopping at depths of several to tens of microns depending on their initial energy. An energy level in the range of about 0.7 MeV to 2 MeV is selected.

When particles enter the crystal, these particles initially lose energy through ionization, so that the crystal lattice is not heated strongly. However, at the end of the particle path, the detectable change in the crystal lattice occurs in a very small, localized region. This region is characterized by the development of displacement spikes caused by the strong local heating caused by the particles stopping at the end of the particle path through the crystal.

The area where the displacement spike develops is a permanent change that can be observed by microscopic examination.

Cooling the crystal during irradiation is intended to keep the crystal's temperature very low, limiting the region to which the structural change caused by the displacement spike is clearly defined. By maintaining the temperature in the range from room temperature to liquefied helium temperature, the desired result is obtained. The temperature of selection is a function of the energy level of the particle and the area depth to be changed. The lattice change in the stop region causes the high-resistance or insulated portion of the crystal that has previously been to be made of a conductive carbon allotrope, i.e. graphite, of low resistance. The transverse range of the pattern is determined by known masking techniques.

The depth of proton penetration into the crystal lattice is directly proportional to the energy level used. Thus, it is possible to produce a lattice that changes to various other depths below the crystal surface.

Natural diamond single crystals are irradiated with protons in the energy range of 0.7 MeV to 1.8 MeV.

The particle beam is supplied by a bender graph accelerator. Every hour about 10 ¹⁶ particles per Cm ² are incident into the crystal with an average beam current of about 1.5 micro amps. All irradiation is performed with the beam out of focus so that the proton intensity distribution of the beam is uniform to eliminate the formation of hot spots. In order to prevent excessive heating of the target, the target is not irradiated with a high particle flux and cooled to a liquid nitrogen temperature (77 ° K) during the irradiation. The investigation period ranges from several minutes to several hours. After 30 minutes of irradiation the formation of a pale dark layer is very evident. Under the conditions of such investigation, the actual dimension is approximately as follows.

Average thickness of the crystals: 1-2 mm,

Depth of modifying layer below crystal surface: approximately 15 microns,

Thickness of the altered layer: about 1 micron or less.

The resistance of the diamond is measured above 250 megohms, but the resistance of the modified layer is measured below 500 ohms. This indicates that the conductivity is increased by 10 ⁵ times or more. The measurement method is as follows.

Electrical contacts face the diamond surface and are placed across the conductive layer.

Such techniques can be used as electrical, electronic and integrated circuits.

As shown in FIG. 3, the integrated circuit 20 has a collector region 22, a base region 24, and an emitter region 26. The integrated circuit, i.e., the semiconductor circuit 20, is separated into an isolation region, for example a lateral isolation region of the dielectric. The lower portion of the substrate is formed with a diamond insulating layer 30 and the upper portion is formed with a diamond insulating layer 32. The method of the present invention is used to form a conductive graphite contact region 34 extending from the underlying insulating diamond lattice 30 to the collector region 22. The structure of FIG. 3 may be mounted in a package or areas 30 and 32 may represent packaging. Thus, the graphite region 34 may be considered as a terminal on the packaging.

Another use of the electronic device shown in FIG. 3 may be an optical semiconductor because the diamond layers 30 and 32 become optical transmitters. The device may be a photodiode or a photosensor. The use of diamond layers 30 and 32 and the process of the present invention enable the use of diamond layers and also provide a method of forming electrical contacts to semiconductors and integrated circuits in a package when it is an optical transmitter. .

The diamond layers 30 and 32 also provide good resistance to radiation and provide good thermal conductivity. This eliminates the need to separate the heat sink from the insulating layer, in which case the heat sink becomes the diamond layers 30 and 32. The method described above is performed at various energy levels to form a three-dimensional contact 34.

The treatment process of the present invention can also be used to form the electrical device shown in FIG. This process is used in the diamond layer or substrate to form the plates 42 and 44 of the capacitors, which are separated from each other by the diamond grating unchanged. The contact area 46 of the conductor extends from the upper plate 42 to the surface of the diamond substrate 40 and the resistive area 48 is formed in the diamond grains using the method of the present invention.

The treatment process of the present invention can also be used to form a circuit board, which is made of diamond so that it can withstand a high heat atmosphere. A diamond lattice circuit board 50 is shown in FIG. 5, the circuit board having an upper layer 52, and a diamond lattice circuit board 50 being shown in FIG. 5, the circuit board having an upper layer 52. ) Is provided with an upper conductive pattern 52 formed of a conductive layer 54 of a via or a passage connecting the lower conductive pattern 56 to the lower conductive pattern 56. The method according to the invention is used to form upper and lower conductive patterns 52 and 56 as well as passages or vias 54.

The conductivity or resistivity of the individual graphite layers is a function of the amount of graphite lattice per unit area as well as the depth or cross-sectional area. The transverse definition of the pattern is accomplished by a known masking method using a metal plate or by a device that can transfer fine beams and move them transversely. As described above, the depth or position of the conductive region in the diamond crystal lattice is a function of the energy of the high energy particle beam as well as the cooling process to limit the particle beam to the set plane.

Due to the emergence of optical transmission for use in memory devices and microprocessors, the use of optically transparent diamond and the technique of forming a conductive layer in the diamond are very useful.

It is clear from the preferred embodiments described above that the object of the present invention can be achieved.

While the invention has been shown and described in detail, it is intended that the invention be described by way of illustration of the invention, not for the purpose of limitation of the invention, and the spirit and scope of the invention should be limited only by the claims. shall.

Claims (10)

Preparing a diamond lattice substrate, and irradiating and selectively heating portions of the diamond lattice with charged particles of a predetermined energy level, thereby providing a graphite conductive region under the surface of the diamond lattice substrate, the diamond lattice substrate Reversibly deforming the portions respectively to an electrical contact point on the surface of the diamond lattice substrate; and reinforcing the diamond lattice substrate during the irradiation to limit the graphite conductive region to a predetermined planar region at a predetermined depth within the diamond lattice substrate. Cooling and forming a conductive region on a diamond lattice substrate comprising connecting the graphite region with a power source such that the graphite region acts as an electrical coin region. The method of claim 1, wherein the diamond lattice substrate is cooled in a range of 4 ° K to 290 ° K. 10. The method of claim 1, wherein the irradiation period is in the range of several minutes to several hours. The method of claim 1, wherein the charged particles are selected from a group of protons, neutrons, and alpha particles. The method of claim 1, wherein the selective heating by irradiation to the diamond lattice substrate is performed as monoenegetic charged particles, wherein the conductive graphite region is the same space as the region in the lattice where the energy stops. A method of forming a conductive region in a diamond lattice substrate overlying a diamond lattice substrate. The method of claim 1, wherein the energy is in the range of 0.1 MeV to 4MeV. A conductive region in the diamond lattice substrate which calls the graphite conductive region formed by heating locally under the surface of the diamond lattice, and a conductor contact formed on the surface of the diamond lattice substrate so as to connect a current to the conductive region; And an electric power source connected to said conductor contact. On the surface of the diamond grating substrate so as to locally connect a diamond grating substrate so as to connect a current to the conductive area in the diamond grating substrate comprising a conductive graphite region formed under the surface of the diamond grating substrate. And a power supply connected to the conductor contact formed on the conductor contact. On the surface of the diamond grating substrate so as to locally connect a diamond grating substrate to connect the conductive region in the diamond grating substrate including a conductive graphite region formed under the surface of the diamond grating substrate and the electrical conductivity to the conductive region. And a power supply connected to the conductor contact formed on the conductor contact. A package for an electrical device, comprising: an electrical device in the package, a power source external to the package, and a plurality of conductive terminals interconnected with the electrical device and an external electrical power source, each conductive terminal being the diamond; A package comprising a diamond lattice thin film for locally heating the lattice to provide a conductive region of three-dimensional graphite formed under the surface of the diamond lattice.

Images