CN87103486B

CN87103486B - Glod platinam containing single crystal silicon interchangeable termistor and its producing method

Info

Publication number: CN87103486B
Application number: CN87103486A
Authority: CN
Inventors: 韦风辉; 李国华; 柳培立
Original assignee: Xinjiang Technical Institute of Physics and Chemistry of CAS
Current assignee: Xinjiang Technical Institute of Physics and Chemistry of CAS
Priority date: 1987-05-07
Filing date: 1987-05-07
Publication date: 1988-08-10
Also published as: CN87103486A

Abstract

The present invention provides a gold-mixing platinum-mixing monocrystal silicon exchange thermistor and a making method thereof, which belongs to the technical field of temperature sensors. The present invention mainly adopts the method that impurities of gold and platinum are mixed in P-shaped monocrystal silicon, so that the thermistor has the characteristic of negative temperature, the B value of the thermistor is 3850K, the deviation distribution of the B value is smaller than plus or minus 0.3%, and the use temperature range is from-50DEG C to 100DEG C. The B value of the thermistor of the present invention is moderate, and the thermistor has the advantages of favorable exchange performance, easy manufacture and low cost, so the thermistor of the present invention is an ideal element for making linear assemblies having linear output. The thermistor can be widely used in the operative technology fields of temperature measurement, temperature control, etc. in medical instrument industry, food industry, household electric appliances, etc.

Description

A kind of unicrystalline silicon thermistor and manufacture method thereof with negative temperature coefficient of resistance

The present invention relates to a kind of unicrystalline silicon thermistor and manufacture method thereof with negative temperature coefficient of resistance.

Be used in the monocrystalline thermistor that the method for mixing deep-level impurity in the monocrystalline silicon makes, the consistency of its resistance-temperature characteristics is greatly improved than oxidate semi-condcutor thermo-sensitive resistance, can satisfy the interchangeability requirement in using preferably, obtains increasingly extensive application.

Tokyo Zhi Pu Electric Co., Ltd once proposed a kind of manufacture method (the clear 58-32481 of Japan's special permission) of silicon single crystal thermal sensitive resistor.They adopt the method for mixing golden impurity in P type or N type silicon single crystal, made the thermistor with negative temperature coefficient, its B value is 4900K, and the deviation profile of the resistance in the time of 30 ℃ is less than ± 0.5%, but minimum serviceability temperature only reaches-20 ℃, and is not to exchange.About the exchange performance being played the discrete case of the B value of main influence, in this patent documentation is open, do not provide the result.The product advertising introduction of the silicon thermistor that provides according to Tokyo electronics Institute of Metallurgical Technology, it is-30 ℃～100 ℃ that this product uses warm area, the deviation profile of B value is ± 2～3%, the deviation profile of resistance is ± 2% in the time of 25 ℃, and this reflects the main performance index of present silicon single crystal thermal sensitive resistor.

The interchangeability of the thermistor that proposes for the satisfied temperature measuring instrument requires and is produced on the needs of the linear modules that has linear output in the broad warm area, wish to obtain the B value at 4000K or lower silicon single crystal thermal sensitive resistor, simultaneously, the deviation profile of its B value requires littler than existing product.And purpose of the present invention, just provide a kind of in p type single crystal silicon gold doping, the method for mixing platinum, thereby obtain the B value and be 3850K, the use warm area is-50 ℃～100 ℃ a single crystal silicon interchangeable thermistor, the deviation profile of its B value is less than ± 0.3%, the deviation profile of resistance is less than ± 0.3%, to satisfy the interchangeability requirement of degree of precision in the time of 25 ℃.

Thermistor provided by the present invention is to mix gold and two kinds of impurity of platinum in P type silicon single crystal simultaneously, makes in the forbidden band to occur apart from the platinum donor level of top of valence band 0.30ev, the golden donor level of 0.35ev and the platinum acceptor level of 0.36ev.When original shallow acceptor concentration in the concentration ratio monocrystalline of these energy levels was a lot of greatly, because the compensating action of these energy levels, material presented negative temperature characteristic, and its B value is about 3850K.The method of mixing gold and platinum in P type silicon single crystal simultaneously mainly adopts the method for diffusion, promptly selects for use the P type silicon single crystal of high resistant rate to make substrate, at first spreads platinum down at 1200 ℃, makes the atomic concentration of platinum reach 1 * 10 ¹⁴/ centimetre ³More than, be 800 ℃～1200 ℃ diffusion gold down in temperature then, make monocrystalline silicon reach satisfactory resistivity.The temperature of diffusion gold is high more, and the resistivity that obtains is high more.Under different gold doping temperature, its B value can be adjusted between 3800K～3900K; Through the silicon single crystal of twice diffusion, and be cut into the thermistor that the chip of 1mm * 1mm is made, its room temperature resistance value can be adjusted between hundreds of ohm to tens kilohm.

Accompanying drawing 1 for gold doping, mix the contour structures schematic diagram of platinum single crystal silicon interchangeable thermistor.Wherein, the method for the available chemical nickel plating of double-sided electrode (2) of chip (1) is made.Lead-in wire (4) is the silver-coated copper wire of 0.2mm, is welded on the electrode (2) with scolding tin (3).Entire chip seals with epoxy resin (5).Utilize the resistance-temperature characteristic of the thermistor that above-described method makes can be referring to accompanying drawing 2.Ordinate among the figure (logarithmic coordinates) is the resistance R of thermistor, and unit is ohm (Ω).The abscissa of Fig. 2 below be absolute temperature inverse (1000 * 1/T), marked corresponding celsius temperature scale on the abscissa of Fig. 2 top.As shown in Figure 2, in-50 ℃～100 ℃ warm area scopes, it satisfies R=R fully ₀EXP(B/T) exponential relationship, the B value is about 3850K; The deviation profile of element B value is less than ± 0.3% in batches; The deviation profile of 25 ℃ of resistances is less than ± 0.3%; In-50 ℃～100 ℃ warm areas different resistive elements be not more than in the deviation profile of the resistance of same temperature spot ± 2%, can reach the requirement of exchanging in batches, simultaneously, resistive element was through 1000 hours, behind 100 ℃ of high temperature ageings, its resistance deviation is less than ± 0.5%, time constant is 1.5～5(second) dissipation factor reach 1.5～2.5(milliwatt/℃), and practical technique field such as this resistance is easy to manufacture, with low cost, the thermometric that is widely used in industries such as Medical Instruments, food industry, household electrical appliance, temperature control.Because the B value of this resistive element is moderate, interchangeability is good, so it is the ideal element that preparation has the linear modules of linear output.

Embodiment.Adopting resistivity is the P type silicon single crystal of 148 ohmcms, is cut into the wafer of 0.3 millimeters thick, after polishing, cleaning, is coated with source platinum expansion 6 hours under 1200 ℃; The platinum source restrains in 5 with specpure chloroplatinic acid and the pure alcohol of top grade: 95 milliliters ratio is made into.The oxide layer that wafer after the diffusion is removed silicon chip surface with hydrofluoric acid, gold was expanded 2 hours in the source that is coated with under 1200 ℃ again; Jin Yuan restrains in 5 with specpure chlorauride and the pure alcohol of top grade: 95 milliliters ratio is formulated.Wafer after the secondary diffusion carries out chemical nickel plating through after removing oxide layer; The prescription of nickel-plating liquid is nickel chloride 30 grams, inferior sodium phosphate 10 grams, ammonium chloride 50 grams, ammonium citrate 65 grams, deionized water 1000 grams.At last wafer is divided into 1 millimeter * 1 millimeter chip, the silver-coated copper wire of 0.2 millimeter of φ in the soldering of the two sides of chip; Wore out 800 hours 100 ℃ of following temperature, resistance is the element of 5.60K Ω when obtaining 25 ℃ behind mechanical resistance trimming.During encapsulation, being coated with the organic-silicon-modified polyurethane of one deck earlier is PPS glue (component 1 48%, component 2 52%), uses E again ₅₁The type epoxy sealing.E ₅₁Type epoxy resin: polyethylene polyamine=10 gram: the ratio preparation of 0.9 gram, and add 1% alumina powder and an amount of colorant and do filler.The element that makes so all can reach the index that proposes previously through every index test.

Claims

1, a kind of unicrystalline silicon thermistor with negative temperature coefficient of resistance, be as sensitive body by the doped P-type silicon single crystal wafer, two sides at said p type single crystal silicon chip forms electrode with chemically coated nickel method, on formed nickel electrode, constitute as lead-out wire with soldering welding silver-coated copper wire, it is characterized in that doped P-type monocrystalline silicon sensitive body be in p type single crystal silicon, mix platinum and gold doping simultaneously and form have a negative temperature coefficient of resistance, the B value is 3850K, B value deviation profile is less than ± 0.3%, the resistance deviation profile is less than ± 0.3% in the time of 25 ℃, the use warm area is-50 ℃～+ 100 ℃ a silicon single crystal wafer, and unicrystalline silicon thermistor is with epoxy resin enclosed.

2, the manufacture method of the described unicrystalline silicon thermistor of claim 1 comprises:

(1) select for use the p type single crystal silicon of high resistivity to make substrate, under 1200 ℃, mix impurity platinum with the source diffusion method of being coated with, the platinum expansion time is 6 hours, makes pt atom concentration reach 1 * 10 ¹⁶Centimetre ³More than;

(2) down mix the impurity gold with the source diffusion method of being coated with at 800 ℃～1200 ℃, expanding the golden time is 2 hours, makes the monocrystalline silicon after the doping have negative temperature coefficient of resistance, and the B value is 3800K to 3900K, and resistivity reaches desirable value;

(3) on two sides, form nickel electrode with chemically coated nickel method through the silicon single crystal flake behind twice diffusing, doping;

(4) silicon single crystal flake of Ni plated electrode is divided into 1 millimeter * 1 millimeter chip, and on the chip two sides with soldering welding silver-coated copper wire as lead-out wire;

(5) chip that welds lead-out wire wore out 800 hours down at 100 ℃, adjusted resistance value with mechanical resistance trimming method then;

(6) use epoxy resin enclosed unicrystalline silicon thermistor.