CN1068006A - Silicon heating component - Google Patents

Abstract

A kind of silicon heating component comprises the electrical insulating substrate (A) of a high-termal conductivity, and a silicon layer (B) and electric contact (C) are being carried in this substrate (A), and the most handy beryllium oxide or aluminium nitride are made substrate (A).Silicon layer (B) is made up of polycrystalline or amorphous silicon, the P type that wherein mixes or N type semiconductor dopant, and preferably doping content is higher than 10 ¹⁸/ cm ³Electric contact is resistant to elevated temperatures, and is fused on the silicon layer (B).In addition, the refractory metal contact layer (C ') that contacts with electrical insulating substrate (A) by one deck of electric contact and a kind ofly be fused to second temperature-resistant material on the contact layer (C ') (C ") forms.By making silicon heating component on the electrical insulating substrate (A) that polycrystalline or amorphous silicon layer (B) is coated to high-termal conductivity.

Description

Silicon heating component

The present invention relates to a kind of silicon heating component, illustrated as the application for patent that Yugoslavic application number is 1097/85, the applying date is on June 28th, 1985, and manufacture method.

Traditional electric heater has a heating element, and this heater efficiency is low, and especially at open design (at this moment, be not force heat is sent in the load from thermal source) and low during with medium heating-up temperature (up to 400 ℃), efficient is low.Its major reason is with respect to desired working temperature, heating-up temperature very high (about 800 ℃): owing to the heater of high temperature to around radiations heat energy lose most of heat energy, result only some heat energy arrives active position.

Traditional heating element is made by the Cr-Ni-Fe-Al alloy, and its resistance is approximately 0.04 Ω/cm.The thermal conductivity of the lower resistivity of this heating material and difference has determined its occupation mode: heater is made coil form, it must insulate with firm pottery or suitable insulating material, and used pottery or suitable insulating material itself also have low thermal conductivity.At last, with metal shell element protection is got up.Such element quality is big, and just can make heat arrive heating location as quickly as possible when making it be heated to about 800 ℃ owing to thermal conductivity is low.The high temperature of heating element causes heat to all directions radiation efficient to be reduced.This in particular concerns less heating component, as the family heater tool.

The essential problem that the traditional heating element can not obtain higher efficient is that the transfer mode of heat is from heating-thermal source-up to service area-load.So transmission far away mainly is confined to radiation, thereby efficient is inevitable quite low, and energy loss is quite big.If satisfy following condition, then can obtain high efficiency:

A, low as much as possible as the thermal resistance of the material of the workpiece of heating element itself;

The quality of b, heating element is as much as possible little;

C, the thermal resistance from the thermal source to the load are also low as much as possible;

The difference of d, working temperature and heating-up temperature is as much as possible little.The traditional heating element can not satisfy these requirements.

Just can easily make traditional wire heater with simple technology (for example filament winding being made coil).In in the past 60 years, traditional heating element is widely used, and conserve energy does not also become the power of the energy-conservation heating element of further development of new.Only in recent years, conserve energy became the important topic of modern technologies, and traditional heater conserve energy effectively.Nowadays, it is especially important that energy savings becomes, and a kind of heating element is all expected to develop in the whole world makes substantial progress the more economical research work of its energy consumption.

The invention provides a kind of novel heating element of being made by polycrystalline that mixes or amorphous silicon, its heating-up temperature is up to 400 ℃.The thermal conductivity of polycrystalline or amorphous silicon approximately is 5 times of wire material of conventional heater.Therefore, heat energy can be delivered to the heat dissipation position with the energy loss of minimum.This novel heating element comprises 6 basic configurations:

1, a kind of element that constitutes by electrical insulating substrate with high thermal conductivity, the polycrystalline that coating one deck mixes on it or the working lining of amorphous silicon, and the surface electrode that is connected with working power.

2, a kind of for making resistance reach the best element of wherein surperficial zone of heating being made wave.

3, a kind of connection contact element of strengthening with refractory metal (Mo, Tu, W etc.) conductor layer.

4, a kind of be placed in suitable, by the metal suprabasil element of high-termal conductivity.

5, a kind of suprabasil element of being made by high-termal conductivity metal (Al, Cu or metalloid) that is arranged to after making, it is directly transferred to heat in the heat load from thermal source.

6, a kind ofly built up " interlayer " shape and had the element of the connection contact of fusion by above-mentioned two elements, it can form cascaded structure or parallel-connection structure to adapt to supply voltage and to obtain power demand.The structure of this derivation can make up with the structure 5 with high thermal conductivity substrate, and its three side sealing closes, and outconnector is on fourth face.

Important meaning of the present invention is based on following 2 reasons:

1, polycrystalline or amorphous silicon are than single crystal silicon semiconductor cheap 50 to 100 times.

2, polycrystalline or amorphous silicon can be coated in the substrate with film (thickness scope from 0.1 to 1 μ m) form.Utilize and select etching technique (for example known semiconductor technology), just this film can be made more suitably surface texture shape (for example bent waveform), and selecting to provide better possibility aspect the gratifying component resistance.

Other characteristic and the single crystal silicon semiconductor of polycrystalline or amorphous silicon are closely similar.This specially refers to high-termal conductivity and metallurgical alloy characteristic, and these are exactly the main cause why silicon is selected as new material.

Narrate the general characteristic and the special characteristics of silicon below, these characteristics make silicon be better than the used material of conventional heater:

1, the material of conventional heater has a definite resistivity, and it can not change.And the resistivity of concrete used silicon can several magnitude on a large scale in change, both can make its change by processing method, also can make its change by later heat treatment method.So just can make heater obtain needed resistance with the quality of minimum.

2, the thermal resistance of silicon is than low 5 times of traditional heater strip material.Silicon can be fully and metal alloying, therefore, just can be made into to the working lining of heater with other material melting welding or hard solder and to connect lead-in wire.Utilize the welding or the fusion characteristic of silicon the energy loss of heat with minimum can be directly transferred on the heat medium.In traditional silk heater, this is impossible.

3, utilize diffusion of chemical vapor deposition (CVD) technology or low-pressure chemical vapor deposition (CPCVD) technology or depositing silicon, just can in substrate, apply the extremely thin silicon of one deck.Said technology cheaply is fit to again produce in batches, and the small investment that needs.Resulting in this way thin layer can mix in deposition process, and its doping is controlled, and so just can give the concrete resistivity of determining this layer earlier.Can also after being deposited in the substrate, this mix.Improved the flexibility of manufacture process like this.

4, utilize suitable technical process, silicon is covered by the dioxide film.This is one deck quartz glass, and it makes silicon layer avoid further oxidation effectively, and makes its surface passivation.The dioxide film directly grows from silicon layer, and therefore, the danger that produces the crack drops to minimum degree.

5, the temperature coefficient of silicon resistor is positive, and its resistance value increases with the rising of temperature.This characteristic of silicon heating component can be used to do inherent overload protection.In suitable structure, a part of heater can also be used as temperature sensor.Polycrystalline or amorphous silicon layer keep positive temperature coefficient of resistance up to 600-800 ℃, and the height of ceiling temperature depends on doping.

In order to obtain best silicon heating component, the present invention has at utmost utilized the above-mentioned characteristic of silicon, and this heating element utilizes the whole described advantage of this material, perhaps only utilizes a part wherein as required.

Describe with reference to the accompanying drawings.

Fig. 1 represents the schematic diagram of the configuration 1 of silicon heating component of the present invention.Polycrystalline or amorphous silicon layer B are coated on the potsherd A.Silicon layer B mixes in coating process or undopes when applying and mixes afterwards.Contact C is positioned at the end of potsherd and fuses on silicon layer B.The surface does not have composition to form, and obtains suitable resistance by the shape of sheet A, the thickness of silicon layer B and the doping of silicon layer.

New, energy-saving silicon heating component as shown in Figure 1 makes heat energy pass in the heat load from the thermal source orientation, this should give the credit to, on electrical insulating substrate A with suitable surface configuration and high-termal conductivity, coating one deck polycrystalline or amorphous silicon B, it or in coating process, perhaps after the silicon layer coating is finished, be higher than 10 with P type or N type semiconductor dopant ¹⁸/ centimetre ³Concentration under mix, in the end of this silicon surface, fuse resistant to elevated temperatures contact C, so that be connected with power supply.

Fig. 1 a represents to realize the preferred plan of the inventive method, and this will describe in the back in conjunction with the embodiments.

Fig. 1 b is the view after amplifying from the single heating element that the sheet shown in Fig. 1 a downcuts.

Fig. 2 is the schematic diagram of configuration 2 of the application's heater, and is different with configuration 1, and refractory metal (Mo, Ta, a W or metalloid) layer C ' who has contact figure (Fig. 2) here at first is coated in base end.Coating silicon layer B uses the mask etching shown in Fig. 2 b then on whole surface; Make the contact C that also can be connected with layer B and layer C ' combination with power supply thereafter, " not only fused with the silicon layer section but also with refractory metal C ' fusion (Fig. 2 C(details K)).Because the refractory metal contact can bear load force under up to 600～800 ℃ high temperature, therefore, this structure is suitable for working under the condition of high temperature.

A kind of distortion of Fig. 3 presentation graphs 2, but silicon layer B graph line is made bent waveform or similar required form with mask lithography and etching method, so that when needed (for example operating voltage higher and under the situation that heating current intensity is little), obtain higher heater resistance.

A kind of distortion of heater shown in Fig. 4 presentation graphs 1,2 and 3 has layer of silicon dioxide overcoat D on polycrystalline that mixes or amorphous silicon layer B.By under high temperature (1000 ℃); in the oxidizability water vapour atmosphere, make silicon layer B oxidation and obtain this layer overcoat; thereby conductive layer is covered by silicon dioxide insulating layer D; insulating barrier D makes effective zone of heating passivation and zone of heating shielded, thereby has improved its fail safe and durability.When doping is when carrying out in coating process, above-mentioned processing step just takes place in diffusing, doping agent in silicon layer, promptly in its dispersion and it is taken place uniformly simultaneously.Therefore, obtain overcoat by oxidation and do not need other processing step.

Fig. 5 represents a kind of distortion of heater, and wherein, heater is installed in metal (for example Cu, an Al or metalloid) pedestal E with high-termal conductivity and upward forms a heating unit.This has provided a kind of heating element of combination, and its heat carries out in the scope of heating element itself to the first step of hear rate location transmission from heating location.Pedestal E passes to heat energy in the heat load from thermal source.

In heater shown in Figure 6, two heating elements shown in Fig. 1 to 4 are arranged, these two elements combination become " interlayer " I, it makes heating power at double in simple mode, and " sealing " heater structure is carried out from the first step that heater is sent to the heat transmission of load heat by pedestal F in " interlayer " I inside of heating element shown in Figure 6.It is the zone of hatching in Fig. 6.

To connect the contact fusion and make two heating elements be combined into " interlayer " shape structure, and make two heating elements form series connection or in parallel construction unit, to adapt to supply voltage and to obtain required power.This sandwich is placed in one by in the metal substrate of high-termal conductivity in the mode of sealing.

In all configurations of above-mentioned novel silicon heating element, key is: apply silicon fiml in substrate, substrate should be that electrical insulator is again outstanding heat carrier simultaneously.Because therefore the working temperature height, is suitable with ceramic material do substrate.Yet the poor thermal conductivity of pottery.Up to several years ago, with regard to thermal conductivity, than other ceramic material superior only be ceramic material beryllium oxide (BeO), the thermal conductivity of its thermal conductivity and fine aluminium is about equally.Unfortunately, BeO is an extremely toxic substance, thereby its application is restricted.

In in the past 5 years, the development of world's high-tech has caused a kind of birth of new ceramic material, the characteristic of this new ceramic properties of materials and BeO is closely similar, but its totally nontoxic, and considerably cheaper, Here it is aluminium nitride (AlN), therefore, although under the optional situation of the high-termal conductivity of substrate, the substrate of other material can be satisfied some requirement, but in the present invention, we at first selected AlN does the substrate of novel silicon heater.

Silicon heating component of the present invention has been represented a kind of novel and Promethean parts, can imagine that the possibility of its commercial Application is very big.Can illustrate that from two aspects it is bound to be applied:

1, produces silicon heating component in the scope that does not exceed the industry relevant, with its parts as corresponding utensil of production and equipment with semi-conductor industry.

2, concerning in all, the low power electric heating products, because saves energy becomes important, and require reduced in size, weight and price, therefore, can imagine that the applying silicon heating element is significant in these products.

Because these elements can use under up to 600 ℃ temperature, therefore, wish that its application is not limited only to family heater (electric radiator), cooker and all widely used electric heating appliances, but also should widen some special professional utensil.

Should be importantly: this element be not only because its higher efficient and can conserve energy, and when producing several utensil owing to use this novel heating element respectively economical with materials effectively.For reduced in size, can directly insert it in the calandria or in its nearest place, therefore promptly just in time on must the position of heating, and leave out hard insulator and heat transfer unit (HTU), a large amount of quality in the heating appliances of today is this two-part quality.

In addition, undersized, directly actuated possibility and temperature registration will cause such can not have in the past, also unthinkable application now.

Referring now to the following examples the preferred plan that realizes the inventive method is described, the following examples are subdivided into step a to f, adopt aluminium nitride (AlN) to make dielectric base A.

Embodiment

A, be of a size of 5 * 5 to 10 * 10cm(Fig. 1 square AlN sheet a) and be put into later on the quartzy rest that is fit in low pressure chemical air pressure deposition (CPCVD) reactor in clean.Simultaneously 20 to 40 such AlN sheets are placed on (according to the type of reactor) on the rest.The AlN sheet by two together, two vertically be placed on the rest together, thereby but have only one side to be exposed to outer depositing silicon, the temperature in the reactor is necessary for 800 °～850 ℃, admissible error 0.25%.

B, when the pressure in the reactor reaches minimum, the silicon carrier of gas is imported in the chamber of reactor, we make the carrier material of silicon with silane or dichlorosilane; If select doping process and deposition process to carry out simultaneously, then can be simultaneously the carrier gas of dopant be imported in this chamber.The amount of dopant must guarantee that the concentration of dopant in the doped layer is from 10 ¹⁸To 5 * 10 ²⁰Individual dopant atom/cm ³The temperature coefficient of concrete layer resistance and layer resistance depends on the amount of dopant, and these parameters can be controlled by mixing.Operating pressure in the chamber of the reactor must be between 30～150KPa.The speed of layer deposition depends on the size of pressure, but according to effectively measuring, the size of its characteristic and pressure is irrelevant.The thickness of sedimentary deposit must be in the scope of 10 to 20 μ m.Depositing to the needed time of such thickness is 30 to 60 minutes, and it depends on the pressure in the chamber of the reactor.

C, behind deposition silicon layer on the sheet, sheet is taken out from reactor, then these slice, thin pieces are placed under 1150 ℃ the temperature to keep 60 to 90 minutes.In this scheme, deposition is not mixed during silicon layer, doping be in the process of above-mentioned high-temperature process with semi-conductor industry in known method carry out.After high-temperature process, layer resistance must be 5～10 Ω/.High-temperature process is partly carried out in the atmosphere of oxidation, makes its surface form or reach as high as the thick SiO of 1 μ m ₂Layer.

D, utilize photoetching process to pass through etching in HF, through cleaning and dry process is removed SiO selectively ₂, thickness titanium (Ti) layer that is approximately 0.5 μ m is coated on the whole surface of sheet then, then under 800 ℃ temperature, titanium layer and silicon layer is fused.After finishing photoetching, removed SiO in the place of parallel lines ₂Layer, thereby, only realized fusion in the removed place of oxide layer.After fuse step, can the titanium of incomplete fusion be removed with etching method.The slice, thin piece that does not also have cutting that Fig. 1 a represents to make like this.

E, should say so importantly, whole described technical processs all are to carry out " in batch ".An AlN sheet that is of a size of 10 * 10cm has 100cm ²The surface.The specific power of heater is about 1000W/cm ²This just means the heating element that utilizes a part " in batch " technical process to make 250W, continues a few hours, and we just can obtain at least 800 heating elements.The operating time that processing procedure is used is maximum, and this depends on automaticity, and it accounts for the 5-20% of process time, and people's operation only accounts for the smaller portions of operating time.

F, (Fig. 1 a) cuts slice, thin piece, thereby we obtain single heating element according to outline line.Fig. 1 b is the schematic diagram of a this single heating element.Cut with the Buddha's warrior attendant saw or with laser beam, be folded down along these lines of cutting thereafter.

Claims (14)

1, a kind of silicon heating component comprises the electrical insulating substrate (A) of a high-termal conductivity, is carrying one deck silicon layer (B) and electric contact (C) in this substrate (A), it is characterized in that, silicon layer (B) is made up of polycrystalline or amorphous silicon, and contact is resistant to elevated temperatures, and contact is fused on the silicon layer (B).

2, silicon heating component according to claim 1 is characterized in that, electrical insulating substrate (A) is made by a kind of ceramic material, preferably beryllium oxide or aluminium nitride.

3, silicon heating component according to claim 1 and 2 is characterized in that, silicon layer (B) mixed P type or N type semiconductor dopant, and preferably doping content is higher than 10 ¹⁸/ cm ³, particularly use boron or phosphorus.

4, according to the described silicon heating component of arbitrary claim in the aforesaid right requirement, it is characterized in that, electric contact (C) by refractory metal for example the contact layer (C ') of the alloy of molybdenum and manganese and second temperature-resistant material (C ") forms; contact layer (C ') contacts with electrical insulating substrate (A), and (C ") fuses on contact layer (C ') second temperature-resistant material.

5, according to the described silicon heating component of arbitrary claim in the aforesaid right requirement, it is characterized in that silicon layer (B) is to guarantee a mode moulding or an etching of giving fixed resistance, preferably bent wave.

6, according to the described silicon heating component of arbitrary claim in the aforesaid right requirement, it is characterized in that the insulated overcoat D of silicon layer (B) covers, preferably the silicon dioxide overcoat.

7, according to the described silicon heating component of arbitrary claim in the aforesaid right requirement, it is characterized in that, it has at least one and the shared electric contact (C) of another silicon heating component, and these heating elements are that serial or parallel connection connects, and preferably are stacked in together.

8, according to the described silicon heating component of arbitrary claim in the aforesaid right requirement, it is characterized in that it is placed on the metallic substrates (E) of a high-termal conductivity, preferably aluminium base.

9, utilize the described silicon heating component of arbitrary claim in the aforesaid right requirement as temperature sensor.

10, a kind of method of making silicon heating component, wherein, one silicon layer (B) is coated on the electrical insulating substrate (A) of a high-termal conductivity, electric contact (C) is connected on the silicon layer (B), it is characterized in that, silicon layer (B) is made up of polycrystalline or amorphous silicon, and be the thin layer (B) (being preferably in the scope of 0.1 to 1 μ m) that is deposited on the electrical insulating substrate (A), silicon layer (B) mixes with P type or N type semiconductor dopant in the process of its deposition or after deposition, and preferably doping content is higher than 10 ¹⁸/ cm ³

11, method according to claim 10 is characterized in that, by photoetching or with a kind of release agent silicon layer is made concrete shape, preferably makes bent waveform.

According to claim 10 or 11 described methods, it is characterized in that 12, silicon layer (B) is gone up and covered the thin overcoat (D) of one deck, preferably silicon dioxide overcoat.

13, method according to claim 12, it is characterized in that, under about 1000 ℃ to 1150 ℃ temperature, particularly in water vapour atmosphere, with silicon layer (B) oxidation, be preferably in when silicon layer (B) deposited to dielectric base (A) process or after deposition and mix.

14, according to the described method of arbitrary claim in the claim 10 to 13, it is characterized in that the following step:

-at deposition silicon layer (B) before, in the end of dielectric base (A) fusion one deck refractory metal layer (C ');

-go up deposition silicon layer (B) in dielectric base (A) and refractory metal layer (C ');

-utilize mask, the locational silicon layer of refractory metal layer (C ') (B) is etched away a part;

-with electric contact (C ") be fused to that the silicon layer (B) with definite shape is gone up and metal level (C ') on.

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