JPH01243511A - Diamond semiconductor device and manufacture of the same - Google Patents

Abstract

PURPOSE:To obtain a diamond semiconductor device capable of operating at high temperature by using diamonds and/or diamond-like carbon as the material of a diamond semiconductor device. CONSTITUTION:A diamond layer 1 is formed on a substrate 3, and on the diamond layer 1 is formed a DLC layer 2. Since the diamond 1 and the DLC layer 2 is bonded only one contact surface or point in this diamond semiconductor device, there is one junction 4 between the diamond layer 1 and the DLC layer 2. An electrode 22 having lead wires or a conductive layer are provided on the surface of the substrate 3, as well as on the surface of the DLC layer.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a diamond semiconductor device and a method for manufacturing the same, and more specifically, to a flexible diamond semiconductor device that operates at high temperatures and a simplified version of the diamond semiconductor device. Regarding the manufacturing method.

[Prior Art and Problems to be Solved by the Invention] Conventionally, silicon, gallium-arsenide, and the like have been used as materials for semiconductor devices.

However, since the semiconductor device cannot operate at high temperatures, the upper limit temperature at which the semiconductor device can be used (upper limit temperature for use) is limited to a low value.

For example, the upper limit temperature for use of a semiconductor device made of silicon is 150°C, and the upper limit temperature for use of a semiconductor device made of gallium-arsenide is 250°C. As described above, since all semiconductor devices have a low upper limit temperature, they are not suitable for use under severe temperature conditions.

On the other hand, it is known that by using diamond as a material for semiconductor devices, the upper limit temperature for use of the semiconductor devices becomes higher and operation at high temperatures becomes possible.

As a method for manufacturing semiconductor devices using diamond as a material, a manufacturing method using ion implantation has been proposed.

The manufacturing method is, for example, by masking the surface of IIb type diamond, which is a P type semiconductor, with a tungsten wire, and then implanting a carbon ion beam into an N type amorphous diamond. IIb, which is a P-type semiconductor,
An N-type amorphous layer is superimposed on a type diamond to form an NP
There is a manufacturing method that attempts to obtain a diamond semiconductor device formed by forming an N junction.

However, since the amorphous layer has many defects due to carbon tangling bonds, the diamond semiconductor device obtained by the manufacturing method is
Since their performance as semiconductor devices is poor, there are no devices that have sufficient performance to be used as diodes, transistors, etc.

In addition, the method for manufacturing diamond semiconductor devices using the ion implantation method is complicated, and the manufacturing equipment for diamond semiconductor devices used in this ion implantation method is expensive and large-scale. have.

In reality, however, there is a problem in that there are no semiconductor devices that can be satisfactorily used as tie-outs, transistors, etc. even at high temperatures.

SUMMARY OF THE INVENTION In order to overcome the drawbacks of the prior art, it is an object of the present invention to provide a diamond semiconductor device capable of high temperature operation and a simplified method for manufacturing the diamond semiconductor device.

[Means and effects for solving the above problem] The invention according to claim 1 for solving the above problem is a diamond semiconductor device characterized in that it is formed by bonding a diamond layer and a diamond-like carbon layer. Yes, the invention according to claim 2 provides a step of forming a diamond layer or a diamond-like carbon layer on a substrate by vapor phase synthesis, and forming a diamond-like carbon layer on the diamond layer, or forming a diamond layer on the diamond-like carbon layer. A method for manufacturing a diamond semiconductor device, comprising the step of forming a diamond-like carbon layer on a type IIb natural diamond layer by vapor phase synthesis. A method of manufacturing a diamond semiconductor device is characterized in that:

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A diamond semiconductor device and a method for manufacturing the same according to the present invention will be described in detail below.

In the diamond semiconductor device of the present invention, what is important is a diamond layer and a diamond-like carbon layer (hereinafter, diamond-like carbon may be simply abbreviated as DLC, and the diamond-like carbon layer may be simply abbreviated as DLC layer).

) or joined in at least one place.

The diamond layer is a natural diamond or a synthetic diamond that contains impurities in its crystals and has semiconducting properties.

A diamond layer using natural diamond can be formed from single-crystal or polycrystalline type IIb natural diamond, and a diamond layer using synthetic diamond can be formed by forming a diamond layer using synthetic diamond.
It can be formed from single-crystal or polycrystalline diamond, which is a P-type or N-type semiconductor doped with impurities.

In either case, the diamond layer is in the form of a g film.-0 The impurities for forming diamond, which is a P-type semiconductor, include elements from Group MB of the periodic table, which form diamond, which is an N-type semiconductor. Examples of impurities for this purpose include elements of group Vb of the periodic table.

Group MB elements of the periodic table include boron, aluminum,
Gallium, indium, thallium, etc. can be mentioned, and group VB elements of the periodic table include nitrogen, phosphorus, arsenic,
Examples include antimony and bismuth.

The diamond layer is doped with the impurity by mixing the gas of the impurity alone and the compound into the raw material gas to form a diamond layer.

The impurity compounds include halides, hydrides,
Mention may be made of hydroxides, oxides, carbides or nitrides.

Specific examples of simple substances and compounds of the impurities include Bx
H6, B4HIO, CH3BCJl 2, (CTo)
JjL C1, [(CH3) An Brzlg,
[(Ctl+)Jalso]2, GaJ6, (CH:+)+
Ga, (CHj) zGaB+1a, (CHz) 3In
, (CHl)41, N2, NHz, PH:l,
ASH:l, N2)1. , CHzAsBrt, CH
zAsHz, (CI(+)3^S, (CHz)Ji,
SbH3, CI CHt S b C41z, CLSb
Examples include Hg, ((:F3)3Sb).

In the present invention, a simple substance of Group mb elements of the periodic table and compounds thereof may be used alone, or two or more types may be used in combination. Similarly, simple substances of group Vb elements of the periodic table and compounds thereof may be used alone, or two or more types may be used in combination.

The DLC layer is a diamond-like carbon Q film that is a P-type or N-type semiconductor doped with impurities, or a diamond-like carbon thin film that is not doped with impurities.

The impurities doped into the DLC layer are similar to the impurities doped into the diamond layer.

In the diamond semiconductor device of the present invention, a bonded state is formed by laminating the diamond layer and the DLC layer. Various diamond semiconductor devices can be obtained depending on the stacking and bonding methods.

For example, (1) type IIb natural diamond layer (usually
It is a P-type semiconductor. ) on the entire surface or part of its surface
(2) A DLC layer is superimposed on the entire surface or part of the surface of a diamond layer provided on a substrate, and a PN junction, NPN junction, or PNP junction is formed on the substrate. Diamond semiconductor devices formed by forming.

(3) A diamond semiconductor device in which a diamond layer is superimposed on the entire surface or part of the surface of a DLC layer provided on a substrate to form a PN junction, a PNP junction, or an NPN junction on the substrate, (4) Examples include diamond semiconductor devices in which at least one diamond layer and at least one DLC layer are alternately stacked on a substrate to form a PNP junction, an NPN junction, or a PNPN junction.

In any case, the thickness of the diamond layer in a diamond semiconductor device is usually from several hundred JLm to several tens of JLm.
is within the range of

The thickness of the DLC layer in diamond semiconductor devices is typically in the range of several hundred gm to several gm.

The diamond semiconductor of the present invention having the diamond layer and DLC layer bonded as described above has an electrode.

The electrodes typically include a bonded diamond layer and D
It is provided at an appropriate position on the surface of the LC layer, but when a diamond layer or a DLC layer is provided on a substrate, if the substrate is conductive, the substrate can be used as an electrode; When the substrate is non-conductive, the substrate will be provided with electrodes.

The electrode can be provided by depositing a metal or the like. However, if the substrate 3 is made of metal, it is not necessary to deposit it on the substrate side.

Preferably, the thickness of the deposited metal is in the range of tens to thousands.

Examples of metals to be vapor deposited include simple substances such as aluminum, titanium, nickel, chromium, and tungsten, and alloys such as NiCr and stainless steel.

Examples of the vapor deposition method for metal vapor deposition for ohmic contact in which metal is vapor-deposited on the laminate 7 include a vacuum vapor deposition method, an ion beam vapor deposition method, a sputtering method, and the like.

Next, specific aspects of the diamond semiconductor device will be explained with reference to the drawings.

FIG. 1, FIG. 2, and FIG. 3 are explanatory diagrams showing aspects of a diamond semiconductor device according to the present invention.

For example, on a substrate 3 as shown in FIG.

A diamond layer l is formed, on the diamond layer l,
A DLC layer 2 is formed.

In this diamond semiconductor device, the contact surface or contact point between the diamond layer l and the DLC layer 2 is -
Since there are only two places, the bond 4 between the diamond layer 1 and the DLC layer 2 is only one place.

Lead wire (not shown) or conductive layer (not shown)
An electrode 11 having an electrode 11 is provided on the surface of the substrate 3, while
It is also provided on the surface of the DLC layer.

The diamond semiconductor device shown in FIG. 1 can be used as a diode.

Further, as shown in FIG. 2, a DLC layer 2 is formed on the substrate 3, and diamond layers 1 are formed on the DLC layer 2 and separated from each other.

The diamond layers 1 are separate and independent from each other, and each diamond layer 1 is in surface or point contact with the DL (4t), so there are two junctions 4 between the diamond layer 1 and the DLC layer 2.

Lead wire (not shown) or conductive layer (not shown)
An electrode 11B having a
, IID are provided on the surface of the diamond layer.

The diamond semiconductor shown in FIG. 2 can be used as a transistor.

Further, as shown in FIG. 3, a DLC layer 2 is formed on the IIb type natural diamond layer 10.

Similarly to the diamond semiconductor device shown in FIG. 1, the diamond semiconductor device shown in FIG. 3 also has a bond 4 between the diamond layer 1 and the type IIb natural diamond layer 10 at one location.

Lead wire (not shown) or conductive layer (not shown)
The electrode 11 having the following characteristics is provided on each surface of the b-type natural diamond layer 10 and the DLC layer 2.

Furthermore, although not shown, diamond layer 1 or IIb
The molded natural diamond layer IO and the DLC layer 2 may be joined at three or more locations.

Furthermore, a diamond layer 10 or DLC (not shown)
The layers 2 may be stacked alternately on the laminate 7.

In this way, the diamond semiconductor device of the present invention can be used as a diode, a transistor, or a device with other functions by varying the bonding and stacking of the diamond layer and the DLC layer.

The semiconductor device of the present invention can be manufactured by the methods of claims 2 and 3.

In claim 2. As for the material of the substrate.

For example, artificial or natural sintered diamond; metals such as silicon, aluminum, titanium, molybdenum, tungsten, and cobalt, their oxides, nitrides, and carbides, and their alloys; stainless steel; At, 03-
Fe-based, TiC-X1-based, Tie-Co-based and 84C
Examples include -Fe-based cermets and various ceramics. Among these, silicon, which is a conductive material and has low resistance, is preferred.

The thickness of the substrate is not particularly limited, but is several tens of #
It is preferably within the range of Lm to several mm.

A carbon source gas is used as a raw material gas for forming a diamond layer or a DLC layer by vapor phase synthesis.

The raw material gas necessary to form a diamond layer or a DLC layer by the vapor phase synthesis method contains at least a carbon source gas.

The carbon source gas is a gas containing at least a carbon compound necessary to form diamond or DLC.

Examples of the carbon compound include methane, ethane,
Alkanes such as propane, butane, pentane, hexane, alkenes such as ethylene, propylene, butene, alkynes such as acetylene, aromatic hydrocarbons such as benzene, toluene, xylene, naphthalene, cyclopropane,
Cycloparaffins such as cyclohexane, cycloolefins such as cyclopentene and cyclohexene, carbon oxide, carbon dioxide, oxygenated carbon compounds such as methyl alcohol, ethyl alcohol, and acetone, mono(di,tri)methylamine, mono(di, Examples include nitrogen-containing carbon compounds such as tri)ethylamine and aniline.

These can also be used alone.

Two or more types can also be used in combination.

Among these, preferred are paraffinic hydrocarbons such as methane, ethane, and propane, oxygen-containing carbon compounds such as -carbon oxide, carbon dioxide, methyl alcohol, and acetone, and nitrogen-containing carbon compounds such as trimethylamine.

Note that the raw material gas may contain hydrogen gas and inert gas in addition to the carbon source gas.

When carbon source gas and hydrogen gas are used as raw material gases, the molar ratio of carbon source gas/hydrogen gas is 1, usually 0.1/1.
00 or more. If this molar ratio is less than 0.1/100, the precipitation of diamond or DLC may be slowed down or the precipitation of diamond or DLC may not occur.

Examples of the inert gas include argon, neon, helium, and the like. Preferred is argon.

When using an inert gas, for the entire jX material gas,
The amount of inert gas is 5 to 95 mol%, preferably 20 to 90 mol%.

The impurities necessary to make the diamond layer and the DLC layer the desired N type or P type are as described above.

The amount of impurities cannot be specified as it varies depending on the desired characteristics of the target diamond semiconductor device, reaction conditions, etc.; The ratio (impurity element/C) is 10-" to 1O-1, preferably l
O-? ~1O-2.

In both claims 2 and 3, the raw material gas,
Alternatively, a gas obtained by exciting a mixed gas of the raw material gas and the impurity element and compound gas is brought into contact with the target object (substrate, diamond layer, or DLC layer).

As the excitation means in the vapor phase synthesis method according to claim 2, conventionally known methods such as thermal filament CVD, direct current plasma CVD, microwave plasma CVD, and high frequency plasma CVD can be used.

As the excitation means in the vapor phase synthesis method according to claim 3, conventionally known methods such as high frequency plasma CVD method and ion blating method can be mentioned.

In the present invention, for example, the adherend (
A diamond layer or a DLC layer can be formed on a substrate, a diamond layer, or a DLC layer.

That is, the temperature of the surface of the adherend varies depending on the excitation means of the carbon source gas in the vapor phase synthesis method and the cooling of the substrate. , usually to form a diamond layer.

300-1100°C, preferably 400-100°C
0°C, and to form a DLC layer, the temperature is usually room temperature to 5°C.
00°C, preferably room temperature to 400°C.

The reaction pressure is usually 1 when forming a diamond layer.
0--103 torr, preferably 10-760
'torr and when forming the DLC layer,
Usually 10-' to 760 torr, preferably 1G-
'~10 torr.

If the reaction pressure is lower than 10-'torr, diamond may no longer precipitate.

On the other hand, if the reaction pressure is higher than 103 torr, no corresponding effect can be obtained.Similarly, if the reaction pressure is lower than IP'torr, DLC may not precipitate. On the other hand, even if it is made higher than 760 torr, a corresponding effect cannot be obtained.

Next, a specific example 7M of the diamond semiconductor HSS device and its manufacturing method according to the present invention will be described in detail with reference to the drawings.

FIGS. 4 and 5 are explanatory diagrams showing specific aspects of the method for manufacturing a diamond semiconductor device according to the present invention.

For example, as shown in FIG. 4, the method for manufacturing a diamond semiconductor device according to the invention according to claim 2 includes forming a diamond layer l on the substrate 3 by the vapor phase synthesis (step 5). The surface may be polished if necessary.

Next, the DLC layer 2 is formed on the diamond layer 1 by the vapor phase synthesis (step 6).

In this way, the bonding between the diamond layer 1 formed on the substrate 3 and the DLC layer 2 is completed, and a laminate is obtained.

Further, a metal electrode 8 for ohmic contact is formed on this laminate by metal vapor deposition (step 9).

For example, as shown in FIG. 5, the method for manufacturing a diamond semiconductor device according to claim 3 includes forming two DLC layers 2 on the b-type natural diamond layer 10 by the vapor phase synthesis. Step 12).

Further, a metal electrode 8 is formed on this laminate by the ohmic contact metal vapor deposition (step 14).

[Examples] Next, specific examples of the present invention will be described in detail with reference to the drawings.

FIG. 6 is an explanatory diagram showing an example of the diamond semiconductor device of the present invention and its manufacturing method.

Type IIb natural tire mont layer with thickness 100 JLm
0 (P-type semiconductor) was used.

A mask 17 is placed on the surface of the type IIb natural diamond layer lO.
(Step 18). By applying the mask 17, the surface on which the DLC layer 19 was to be formed was exposed.

A mask 17 is placed on the surface of the type IIb natural diamond layer lO.
, and methane gas as the reaction gas.

High frequency plasma CV using hydrogen gas and PH gas
8000 people (7) D LC layer 19 (N[
A semiconductor was formed (Step 20).

The conditions for the high frequency plasma CVD method are as follows.

High frequency power supply frequency: 13.56 MHz Substrate temperature: 3
00°C Pressure; 10-”Torr Flow rate of methane gas, 203CCM Flow rate of hydrogen gas; 20 SCCM Flow rate of mixed gas of PH:I gas and hydrogen gas with PH3 concentration of 2,000 ppm, 53C:CM As described above , the IIb type natural diamond layer lO and the DLC layer 19 were bonded.

Further, while keeping the mask 17 on the surface of the type IIb natural diamond layer 10, the surface of the DLC layer 19 and the type II
A tungsten layer 21 with a thickness of 300 nm was deposited on the surface of the b-type natural diamond layer 10 by ion beam deposition (step 22).

In this way, a PN type diode could be obtained.

When the current-voltage characteristics of this PN type diode at 300 DEG C. were measured, the characteristic curve shown in FIG. 7 was obtained.

As shown in Figure 7, this PN type diode can withstand temperatures of 150°C, where the characteristics of conventional silicon diodes deteriorate.
Even at a much higher temperature of 300° C., it had good semiconductor properties without deterioration due to high temperatures.

[Effects of the Invention] Since the diamond semiconductor device according to claim 1 uses diamond and/or diamond-like carbon as the material of the diamond semiconductor device, it can be heated at a higher temperature than a conventional general semiconductor device. It is possible to make all kinds of operations possible.

Furthermore, the method for manufacturing a diamond semiconductor device according to claim 2 provides a method for manufacturing a diamond semiconductor device that can operate at a higher temperature than conventional general semiconductor devices, and also provides a simple method for manufacturing a diamond semiconductor device. A simplified method for manufacturing a diamond semiconductor device using the apparatus can be provided. Therefore,
Diamond semiconductor devices capable of high temperature operation can be supplied at low cost.

Furthermore, according to the method for manufacturing a diamond semiconductor device according to claim 3, compared to a manufacturing method using conventionally known type IIb natural diamond as a material,
It is possible to provide a method for manufacturing a diamond semiconductor device that has properties that can be fully used as a semiconductor device, and also to provide a simplified method for manufacturing a diamond semiconductor device using a simple device. Therefore, it is possible to supply diamond semiconductor devices capable of high temperature operation at low cost.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing one aspect of the configuration of a diamond semiconductor device according to the present invention. FIG. 2 is an explanatory diagram showing one aspect of the configuration of a diamond semiconductor device according to the present invention. FIG. 3 is an explanatory diagram showing one aspect of the configuration of a diamond semiconductor device according to the present invention. FIG. 4 is an illustrative diagram showing one aspect of the configuration of the method for manufacturing a diamond semiconductor device according to the invention of claim 2. FIG. 5 is an explanatory diagram showing one aspect of the configuration of the method for manufacturing a diamond semiconductor device according to the invention of claim 3. FIG. 6 is an explanatory diagram showing an example of the diamond semiconductor device of the present invention and its manufacturing method. FIG. 7 is a graph showing the current-voltage characteristic curve of the PN type diode obtained in the example. 1... Diamond layer, 2... Diamond-like carbon layer, 3... Substrate, 4... Bonding, 5... Step of forming a diamond layer or diamond-like carbon layer on the substrate, 6... Step of forming a diamond-like carbon layer on the diamond layer or forming a diamond layer on the diamond-like carbon layer, 1O...IIb type natural diamond layer, 12... forming a diamond-like carbon layer on the IIb type natural diamond layer The process of doing. Figure 1 Figure 2 Figure 3 Figure 6

Claims (3)

[Claims] (1) A diamond semiconductor device characterized by being formed by bonding a diamond layer and a diamond-like carbon layer. (2) The feature includes a step of forming a diamond layer or a diamond-like carbon layer on a substrate and a step of forming a diamond-like carbon layer on the diamond layer or a diamond layer on the diamond-like carbon layer by vapor phase synthesis. A method for manufacturing a diamond semiconductor device. (3) A method for manufacturing a diamond semiconductor device, comprising the step of forming a diamond-like carbon layer on a type IIb natural diamond layer by vapor phase synthesis.