CN111647878A

CN111647878A - Thermally and electrically isolated substrate holder

Info

Publication number: CN111647878A
Application number: CN202010735304.8A
Authority: CN
Inventors: 陈亚男; 霍晓迪; 周广迪; 金鹏; 王占国
Original assignee: Institute of Semiconductors of CAS
Current assignee: Institute of Semiconductors of CAS
Priority date: 2020-07-27
Filing date: 2020-07-27
Publication date: 2020-09-11
Anticipated expiration: 2040-07-27
Also published as: CN111647878B

Abstract

The utility model provides a thermal-insulated electrically conductive bias voltage substrate holds in palm, includes support body, graphite spare, bias voltage electrode, insulating part. A substrate is placed on the upper surface of the support body; the graphite piece is a graphite plate or a graphite rod; a bias electrode is connected with the graphite piece; the insulating part with the graphite spare lower surface links to each other, the insulating part links to each other with the cavity wallboard. The insulating portion includes a first insulating member and a second insulating member. The inter-insulated heat conduction bias voltage substrate holder can reduce the temperature fluctuation of the substrate and realize good heat preservation effect under the heating state, can prevent the substrate from transmitting excessive heat to the bias voltage electrode to cause the failure of the bias voltage electrode, saves electric energy and is more beneficial to the epitaxial growth of a high-quality film layer.

Description

Thermally and electrically isolated substrate holder

Technical Field

The disclosure relates to the field of semiconductor material preparation, and in particular relates to a heat-insulating conductive bias substrate holder for epitaxial growth of a film layer in a vacuum environment, especially for large-area diamond film layer growth.

Background

The semiconductor diamond has excellent electrical and optical properties such as ultra-wide band gap, high carrier mobility, high carrier saturation drift rate, high breakdown field strength, large exciton confinement energy and the like, so that the semiconductor diamond has wide application prospect in the aspects of development of high-power microwave devices, power electronic devices and deep ultraviolet photoelectronic devices.

Compared with the single crystal diamond with small area, the single crystal diamond with large area and high quality has strong market demand and application potential. Among the numerous manufacturing methods, microwave plasma chemical vapor deposition is well recognized as the best method to obtain electronic grade single crystal diamond material. Because homoepitaxy is limited by the size of the diamond substrate and the epitaxy cost is high, heteroepitaxy by adopting a large-area substrate is the best mode for preparing large-area high-quality single crystal diamond. Heteroepitaxy still presents a number of problems, of which how to enhance nucleation efficiency and how to increase nucleation density are currently important issues.

The application of a bias voltage to the substrate is an effective way to increase the nucleation density. Currently, the most common method for applying an effective bias to a sample is to directly connect a bias electrode to a support. However, this method has the following disadvantages: the heat of the sample is easy to dissipate through the conduction of the bias electrode, so that the heat of the sample is difficult to maintain, and the temperature fluctuation is large; excessive heat usually causes the resistance value of the bias electrode to change and even the resistance of the bias electrode to fail, and finally causes the bias voltage applied to the sample to change and fail to reach the desired set value.

In addition, in microwave plasma chemical vapor deposition apparatus, the heat source for maintaining the temperature of the substrate is generally derived from two parts, namely, the energy from the microwave conversion and the heating device below the substrate. The heat source obtained by the heating device is expensive, so the device usually adopts the microwave energy conversion method to obtain the heat source. However, in any of these methods, since the substrate holder is easily heat-conductive and causes heat loss, a large amount of electric energy needs to be input to maintain the substrate temperature, which increases the production cost of the product and hinders the realization of industrialization.

Disclosure of Invention

Technical problem to be solved

The present disclosure provides an insulated, electrically biased substrate holder to at least partially solve the above-identified problems.

(II) technical scheme

According to an aspect of the present disclosure, there is provided an insulated and conductively biased substrate holder, comprising:

the substrate is placed on the upper surface of the support body;

the upper end of the graphite piece is connected with the lower surface of the support body;

the bias electrode is connected with the lower end of the graphite piece;

the insulating part is connected with the cavity wall plate; the insulating part with graphite spare lower extreme links to each other, just the insulating part cover is established on the biasing electrode.

As an embodiment of the present disclosure, the graphite member is a graphite plate or a graphite rod.

As an embodiment of the present disclosure, the insulating part includes:

the lower end of the first insulating part extends into the cavity wall plate, and the upper end of the first insulating part is connected with the end part of the cavity wall plate;

and the second insulating part is sleeved outside the first insulating part and sleeved on the bias voltage.

As an embodiment of the present disclosure, a surface of the tray body is provided with a rough area; the support body is made of molybdenum.

As an embodiment of the present disclosure, the biasing electrode is threadedly coupled to the graphite member.

As an embodiment of the present disclosure, the first insulating member is a cap-shaped hollow structure; the second insulating piece is of an annular sheet structure.

As an embodiment of the present disclosure, the bias electrode penetrates through the cap-shaped hollow structure.

As an embodiment of the present disclosure, the first insulating member and the second insulating member have the same height.

As one embodiment of the present disclosure, the material of the insulating portion is alumina and/or quartz.

As an embodiment of the present disclosure, a first end outer diameter of the first insulating member is smaller than a second end outer diameter of the first insulating member.

(III) advantageous effects

According to the technical scheme, the heat-insulating conductive bias substrate holder provided by the disclosure has the following beneficial effects:

based on the characteristics that the thermal conductivity of graphite is reduced along with the rise of temperature and the graphite is insulated at extremely high temperature, the heat-insulation and conductive bias voltage substrate is supported in a heating state, so that the temperature fluctuation of the substrate can be reduced, a good heat insulation effect is realized, the substrate can be prevented from transmitting excessive heat to a bias voltage electrode to cause the failure of the bias voltage electrode, the electric energy is saved, and finally, the epitaxial growth of a high-quality film layer is realized.

Drawings

FIG. 1 is a schematic view of a first embodiment of a thermally and electrically biased substrate holder according to the present disclosure;

FIG. 2 is a diagram illustrating heat transfer during operation of an embodiment of an insulated, conductively biased substrate holder of the present disclosure;

fig. 3 is a schematic view of a second embodiment of a thermally and electrically biased substrate holder in accordance with the present disclosure.

Description of the symbols

1-support body

2-graphite part

3-insulating part

31-first insulator

32-second insulator

4-bias electrode

5-Cavity wall plate

6-substrate

7-graphite rod

Detailed Description

For the purpose of promoting a better understanding of the objects, aspects and advantages of the present disclosure, reference is made to the following detailed description taken in conjunction with the accompanying drawings. The main technical scheme of the disclosure is that a heat-insulation and electric-conduction bias substrate holder is designed by utilizing the characteristics that the heat conductivity of graphite is reduced along with the rise of temperature and is heat-insulated at extremely high temperature.

For the purpose of promoting a better understanding of the objects, aspects and advantages of the present disclosure, reference is made to the following detailed description taken in conjunction with the accompanying drawings.

Certain embodiments of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the disclosure are shown. Indeed, various embodiments of the disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements.

The present disclosure provides a heat-insulating and electrically-conductive substrate holder with bias voltage, wherein the holder body is flat, is made of an electrically-conductive material, such as molybdenum, and is resistant to high temperature and etching, and the bottom of the holder body is roughened to enhance the friction force with a graphite plate. The graphite plate is arranged below the support body, and an inner wire or an inner groove is formed in the graphite plate and used for being connected with a bias electrode below the graphite plate. The top end of the bias electrode is provided with an external wire or a rod which can be connected with the graphite plate. The insulating part is made of high-temperature-resistant insulating material, and is commonly made of alumina. The insulating part comprises two insulating pieces, wherein one insulating piece is in a cap-shaped hollow shape, and the other insulating piece is in a ring shape. Both fittings were of uniform thickness. The insulating part is used for insulating heat of the support body and plays an insulating role; on the other hand, the bias electrode penetrates through the first insulating part, so that the external power supply is facilitated. The graphite plate is connected with the bias electrode and the support body, so that the graphite plate not only can play a role in conducting, but also can isolate heat generated by the substrate in the reaction process, further maintain the temperature of the substrate and prevent the bias electrode from being damaged due to excessive heat.

In view of the above, the present disclosure provides a thermally and electrically biased substrate holder, which includes the following embodiments:

example one

Fig. 1 is a schematic view of a thermally and electrically biased substrate holder according to a first embodiment of the disclosure. As shown in fig. 1, the thermally and electrically biased substrate holder comprises, from top to bottom: support body 1, graphite plate 2, insulating part 3, bias electrode 4. The support body 1 is used for placing a sample, and a graphite plate with the thickness of preferably 3mm to 5mm and the diameter of preferably 50mm to 200mm is arranged below the support body, and is used for insulating the substrate 6, reducing the temperature fluctuation of the substrate 6 and further preventing the substrate 6 from transferring excessive heat to the bias electrode 4 to cause the bias electrode 4 to lose efficacy, and the graphite plate also plays a role in transferring current. The bias electrode 4 is fixedly connected with the graphite plate 2 and used for applying bias voltage, the insulating part 3 is positioned below the graphite plate and used for insulating the support body 1, and the used material is high-temperature-resistant insulating material which is commonly used aluminum oxide. The insulating portion 3 includes a first insulating member 31 and a second insulating member 32, the first insulating member 31 having a cap-shaped hollow structure, and the second insulating member 32 having a ring-shaped sheet structure. The first insulating member 31 and the second insulating member 32 have the same thickness. The insulating portion 3 functions as: firstly, the support body 1 is insulated; secondly, the bias electrode 4 is defined by a hollow insulating fitting for insulation.

The support body 1 is flat and made of conductive, high-temperature-resistant and etching-resistant materials such as molybdenum, and the bottom of the support body 1 is subjected to roughening treatment to enhance the friction force with a graphite plate. The graphite plate is provided with an internal thread or groove for connection to the underlying biasing electrode 4.

The top end of the bias electrode 4 is provided with an external wire or a rod which can be mutually connected with the graphite plate, and is connected with the graphite plate through an internal wire or an internal groove on the graphite plate. The bias electrode 4 penetrates the first insulator 31 of the insulating portion 3.

FIG. 2 is a diagram illustrating heat transfer during operation of an embodiment of an insulated, conductively biased substrate holder of the present disclosure. As shown in fig. 2, in the first embodiment of the thermally and electrically insulated bias substrate holder, in an operating state, heat generated by the substrate 6 is transferred through the holder body 1, and when heat is transferred to the graphite plate, due to the high temperature thermal insulation property of the graphite plate, most of the heat is not transferred to the bias electrode 4 and the cavity wall plate 5, and thus most of the heat remains on the substrate 6 and the holder body 1. Under the same microwave input condition, the temperature difference formed by the top surface and the bottom surface of the substrate 6 of the embodiment of the heat-insulating and conductive bias substrate holder of the disclosure is relatively small, and the uniformity and evenness of the whole temperature are better. In the first embodiment of the heat-insulating and electrically-biasing substrate holder disclosed by the disclosure, when the microwave fluctuates, the heat and temperature fluctuation of the substrate 6 is small based on the heat-insulating effect of the graphite plate, so that the high-quality growth of the diamond film layer is ensured. Because the diamond film layer keeps high quality, the microwave negative feedback is not easily affected by heat and temperature fluctuation. The heat and temperature fluctuations of the substrate 6 are then resolved in multiple cycle feedback, thereby maintaining high quality growth of the diamond film layer. Meanwhile, the insulating part 3 can effectively separate the graphite plate of the heat-insulation and conductive bias voltage substrate support from the cavity wall plate 5 of the microwave plasma chemical vapor deposition equipment, so that the electric quantity loss caused by the conductive phenomenon of the cavity wall plate 5 when bias voltage is applied to the outside is avoided.

This example applied diamond nucleation bias treatment to silicon substrates in the range of 2 inches to 6 inches by using a microwave plasma chemical vapor deposition apparatus. Common process parameters include: the methane concentration is 1% to 10%; the microwave power is 1000W to 6000W; the gas pressure is 10Torr to 120 Torr; the bias voltage is-300V to + 300V; the bias time is 1min to 120 min.

The surface temperature of the substrate 6 can be measured by means of an infrared thermometer. During the bias nucleation, the temperature profile was drawn by measuring the temperature of the substrate 6 at various positions by moving the measurement point of the infrared thermometer. Similarly, the temperature distribution maps of different positions of the substrate 6 of the substrate holder in the prior art are measured, and the temperature distribution fluctuation range of the substrate holder disclosed by the invention is narrower by comparing the temperature distribution maps with the temperature distribution maps, so that the heat insulation conductive bias substrate holder can effectively insulate heat with the bias electrode 4, and the electric energy is saved.

Example two

In a second embodiment of the present disclosure, a thermally and electrically biased substrate holder is provided. Fig. 3 is a schematic view of a second embodiment of a thermally and electrically biased substrate holder in accordance with the present disclosure. As shown in fig. 3, the thermally and electrically biased substrate holder of the present embodiment is different from the thermally and electrically biased substrate holder of the first embodiment in that: the graphite member is replaced by a graphite rod 7, which can also perform the functions of heat insulation and electric conduction, as shown in fig. 3, the heat insulation and electric conduction bias substrate holder in the embodiment comprises: the device comprises a support body 1, an insulating part 3, a bias electrode 4 and a graphite rod 7.

The substrate 6 is placed on the upper surface of the support body 1. The upper end of the graphite rod is connected with the support body 1, and the lower end of the graphite rod is connected with the bias electrode 4. The connection means may be a threaded connection. The insulating portion 3 includes: a first insulating member 31 having a cap-shaped hollow structure; a first end of the first insulating member 31 extends into the cavity wall plate 5, and a second end of the first insulating member 31 is connected with an end of the cavity wall plate 5; a second insulating member 32 having an annular structure; the second insulating member 32 is sleeved outside the first insulating member 31, and the second insulating member 32 is sleeved on the bias voltage; a first end outer diameter of the first insulating member 31 is smaller than a second end outer diameter of the first insulating member 31; the first insulating member 31 and the second insulating member 32 have the same height. The insulating part 3 is made of one or more of alumina and quartz. The bias electrode 4 penetrates through the cap-shaped hollow member of the insulating portion 3.

So far, the embodiments of the present disclosure have been described in detail with reference to the accompanying drawings. It is to be noted that, in the attached drawings or in the description, the implementation modes not shown or described are all the modes known by the ordinary skilled person in the field of technology, and are not described in detail. Further, the above definitions of the various elements and methods are not limited to the various specific structures, shapes or arrangements of parts mentioned in the examples, which may be easily modified or substituted by those of ordinary skill in the art.

From the above description, one skilled in the art should clearly recognize that the thermally and electrically biased substrate holder of the present disclosure is well suited.

It should also be noted that directional terms, such as "upper", "lower", "front", "rear", "left", "right", and the like, used in the embodiments are only directions referring to the drawings, and are not intended to limit the scope of the present disclosure. Throughout the drawings, like elements are represented by like or similar reference numerals. Conventional structures or constructions will be omitted when they may obscure the understanding of the present disclosure.

And the shapes and sizes of the respective components in the drawings do not reflect actual sizes and proportions, but merely illustrate the contents of the embodiments of the present disclosure. Furthermore, in the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

Unless otherwise indicated, the numerical parameters set forth in the specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by the present disclosure. In particular, all numbers expressing quantities of ingredients, reaction conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term "about". Generally, the expression is meant to encompass variations of ± 10% in some embodiments, 5% in some embodiments, 1% in some embodiments, 0.5% in some embodiments by the specified amount.

Furthermore, the word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

The use of ordinal numbers such as "first," "second," "third," etc., in the specification and claims to modify a corresponding element does not by itself connote any ordinal number of the element or any ordering of one element from another or the order of manufacture, and the use of the ordinal numbers is only used to distinguish one element having a certain name from another element having a same name.

Similarly, it should be appreciated that in the foregoing description of exemplary embodiments of the disclosure, various features of the disclosure are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various disclosed aspects. However, the disclosed method should not be interpreted as reflecting an intention that: that is, the claimed disclosure requires more features than are expressly recited in each claim. Rather, as the following claims reflect, disclosed aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this disclosure.

The above-mentioned embodiments are intended to illustrate the objects, aspects and advantages of the present disclosure in further detail, and it should be understood that the above-mentioned embodiments are only illustrative of the present disclosure and are not intended to limit the present disclosure, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present disclosure should be included in the scope of the present disclosure.

Claims

1. A thermally and electrically biased substrate holder, comprising

The substrate is placed on the upper surface of the support body;

the bias electrode is connected with the lower end of the graphite piece;

2. The thermally and electrically biased substrate holder of claim 1, wherein the graphite pieces are graphite plates or graphite rods.

3. The thermally and electrically biased substrate holder of claim 1, wherein the insulating portion comprises:

4. The thermally and electrically biased substrate holder of claim 1, wherein a surface of the holder body is provided with a roughened region; the support body is made of molybdenum.

5. The thermally and electrically biased substrate holder of claim 1, wherein the biasing electrode is threaded with the graphite piece.

6. The thermally and electrically biased substrate holder of claim 3, wherein the first insulator is a cap-shaped hollow structure; the second insulating piece is of an annular sheet structure.

7. The thermally and electrically biased substrate holder of claim 6, wherein the biasing electrode extends through the cap-shaped hollow structure.

8. The thermally and electrically biased substrate holder of claim 3, wherein the first and second insulators are the same height.

9. The thermally and electrically biased substrate holder of claim 1, wherein the insulating portion is made of alumina and/or quartz.

10. The thermally and electrically biased substrate holder of claim 3, wherein a first end outer diameter of the first insulator is smaller than a second end outer diameter of the first insulator.