JPS58112377A - Semiconductor thermocouple - Google Patents

Abstract

PURPOSE:To obtain a high sensitivity thermo electromotive force by a method wherein a radiant energy is absorbed by evaporation conductors respectively evaporated at one end of an N type or a P type region, and a plurality of N type or P type regions are connected respectively in series. CONSTITUTION:On the surface of a disk formed P type semiconductor substrate 10, an impurity such as phosphorus is doped by an ion implantation method, etc., thus a plurality of L-shaped N type regions 11 are radially formed, and then a plurality of L-shaped conductors 12 are evaporated radially into a form symmetrical to this N region 11. Thereafter, a region 13, wherein the top ends of the N type region 11 and the conductor 12 are superposed at the center of the substrate 10, is blackened resulting in the formation of the group of measuring junctions, then N type regions are connected respectively in series, and thereby the resultant thermo electromotive force is obtained from a pair of electrodes T1 and T2. Besides, a P type semiconductor part 10 is formed so that the potential does not become more positive than any part of the N type semiconductor 11.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor thermocouple that measures radiant energy by utilizing thermoelectromotive force of an n-type (or p-type) region formed in a single crystal semiconductor substrate. .

K for miniaturizing infrared gas concentration meters, etc. for portable use, etc.
This requires a small, mechanically strong and stable element, and a thermocouple as shown in Fig. 1 is known as a small and highly sensitive thermocouple. That is, 10 to 15 pairs of gold-constantan thermocouples 2 are connected radially in series on the surface of a disk-shaped substrate 1, and the temperature measuring junctions of these thermocouples 2 are gathered at the center of the substrate. Blackening treatment with gold black or platinum black is done to improve the absorption of radiant energy.
The thermoelectromotive force generated between the reference junction group 3 and the reference junction group 3 is combined in series and output from the terminal 4 to the outside. However, such thermomobiles have a structure made of composite silk and are susceptible to mechanical vibrations, and also have the disadvantage that they require advanced techniques for assembly.

In recent years, prototype thermomobiles with thinner films have been produced, but sufficient sensitivity has not been achieved.

On the other hand, a thin film type thermistor bolometer as shown in FIG. It has a large variation of 4 to 5%/'C and has excellent sensitivity, but it has the disadvantage that power must be supplied from the outside via the base element 7 because it is a passive element. In addition, when a silicon solar cell, which is an active element, is used as a thermal detector, it has advantages such as a quick response, a simple and durable structure, and no need for an external power supply. The effective wavelength range of the battery is 0.45-1
．． Since it has a narrow band of 15 μm, it has the disadvantage that it cannot measure low-temperature bodies below 800°C.

Furthermore, the thermal conductivity detector TCD (Therma/-Con) used in gas chromatograph equipment, etc.
duct IVity Detector),
As shown in Figure 3-(C), a mixed gas mixed with transport gas (carrier gas) K and sample gas G is led to the measurement pipe section 8C, and gas R containing only the transport gas is led to the comparison pipe section 8D. The difference in thermal conductivity between the two gases is detected by the heating resistors 8A and 8B and the other two heating resistors in the comparison tube section through the process of flow or diffusion. However, all of these detectors typically consume power of about 5 W, have a slow response speed of about 0.1 seconds, and have the disadvantage that the structure is complicated to obtain a stable detector. Therefore, an object of the present invention is to provide a semiconductor thermocouple that eliminates the above-mentioned drawbacks and problems.

This invention will be explained below.

The present invention relates to a semiconductor thermocouple, in which a conductor is deposited on a plurality of n-type or p-type regions formed in a single crystal semiconductor substrate and one end of each of these n-type or p-type regions, and radiated energy is generated by these deposited conductors. In addition, a plurality of n-type or p-type regions are connected in series to obtain highly sensitive thermoelectromotive force.

In FIGS. 4A and 4B showing an embodiment of the present invention, the surface of a disc-shaped p-type conductor substrate 10 is doped with impurities such as phosphorus by an ion implantation method to form a plurality of impurities. L
Letter-shaped n-type regions 11 are formed radially, and this n-type region #1
A plurality of L-shaped conductors 12 are arranged radially KM in a symmetrical shape with
wear it. After that, the tips of the n-type region 11 and the conductor 12 are connected to the substrate 1.
The overlapping region 13 at the center of 0 is blackened to form a side hot contact group, and! By connecting the '1fll regions 11 in series, a composite thermoelectromotive force is obtained from the pair of electrodes T1 and T2. Note that the potential of the p-type semiconductor portion 10 is less positive than that of any other portion of the n-type semiconductor 11.

Here, the thermoelectromotive force of the n-type region is θ, the absolute opening degree T
, the conductor level of the semiconductor and the Fermi unit are respectively EC
, EF, and the electron charge is e, the thermoelectromotive coefficient of the n-type region is as follows. Here, for example, phosphorus is 3×10 atoms/crI
In n-type silicon doped to a concentration of The thermoelectromotive rate is approximately 15 times higher.

However, the thermal electromotive force expressed by equation (1) changes depending on the impurity concentration in the semiconductor (change in impurity concentration → change in Fermi level → change in thermal electromotive force), so if a compatible thermocouple is used in a semiconductor, It was difficult to make.

For this reason, in the past, thermal electromotive force was only used to determine whether a single/cn type semiconductor or a p type semiconductor.

However, in recent years, impurity implantation technology has advanced with the advent of ion implantation, and it has become possible to implant impurities into semiconductors in a controlled manner. , compatible high-sensitivity compact semiconductor thermocouples can be easily obtained. In addition, the fifth
1M (A) and (B) As shown in K, a small hole 14 is provided in the overlapping part of the n-type region [11 and the conductor 12, and a circle is formed in the n-type region 11 from this small hole 14 by isotropic and anisotropic etching. A groove-shaped cavity 15 may also be provided.

This cavity is formed into a fixed shape due to recent improvements in single crystal etching technology. This cavity structure efficiently absorbs radiant energy based on the so-called principle of cavity radiation, increasing the absorption effect.The structure of the small hole 14 and cavity 15 can be used not only for thermomobiles but also for individual radiation detection elements. In the example shown in Fig. 4, the plurality of n-type regions are formed in a p-type semiconductor substrate, but they can also be formed on a single crystal semi-insulating substrate such as sapphire. .

In addition, No. 6 (in the garden) and (however) show an example in which the semiconductor device pair of the present invention is applied as a thermal conductivity type detector for a gas chromatograph device, etc. 21 is formed to form a thermocouple element, and after etching the region including the vicinity of both ends, conductors 22A and 22B are vapor-deposited, and the heat of the n-type region 21 is transferred through electrodes 23A and 23B connected to these conductors 22A and 22B. It is designed to output electromotive force. A diffusion region [24] with a high impurity concentration is formed along the n-type region 21 to serve as a heater, and this heater U is heated by supplying electric power from electrodes 25A and 25B. In addition, etched gases *26 and n are arranged so as to be in contact with both ends of the thermocouple element 21, and a plate made of Pyrex glass or the like is installed to cover the entire upper surface between the substrates. ing. Incidentally, a portion 31 on the electrodes 23A and 23B and a portion 32 on the electrodes 25A and 25B of the plate (9) are all removed by etching into a rectangular shape. This structure can also be demonstrated by improving the impurity injection technology into semiconductor single crystal and the etching technology.

In such a configuration, the heater feeder is 1 [25A, 2
5B, and the gas G is heated through the gas groove.
1. When G2 flows in, a temperature difference occurs between both ends of the n-type region 210 due to the difference in thermal conductivity between the two gases G and G2. As a result, the conductors 22A, 22B and the electrodes Z3A,
23B, a thermoelectromotive force corresponding to the temperature difference can be obtained.

On the other hand, FIGS. 7 and 8 each show a modification thereof, and the example in FIG. 7 is such that two gas grooves are arranged side by side, and a thermoelectric element 21 is arranged on the side thereof. This is what I did. Then, the electrode 23A of the thermal lightning element 21 and the heater 1! The thermoelectric element 21 is combined with the pole 25A in one place.
The electrode 23B of the heater U and the electrode 25B of the heater U are put together in one place. Further, in the example shown in FIG. 8, the thermoelectric element 21 is formed in a U-shape, and U-shaped heaters are arranged inside the thermoelectric element 21, and electrodes 23A, 23B, 25A, 25
This is a collection of B in one place. Detection similar to that described above can also be performed using such a device.

In addition, in the above 1, the semiconductor substrate is p-type and the n-type region is used as a thermocouple, and the semiconductor substrate is n-type and p
The molded mold mound may be used as a furnace or an electric couple.

As explained above, the copper conductor thermocouple of the present invention can be easily inserted into a single crystal semiconductor substrate using the ion pillar implantation method or the like.
! Since it can be formed as a highly sensitive and extremely small electrode couple, it is mechanically strong and stable, and is useful for miniaturizing radiation thermometers, gas concentration meters, etc., and is economical because it can be mass-produced.

In addition, although the shape of the semiconductor substrate is circular or rectangular in the above description, the shape is arbitrary.

[Brief explanation of the drawing]

Figure 941 is a front view showing the structure of a conventional thermopile, and Figure 2 is an oblique view showing the structure of a thermistor bolometer.
Figures 3 (5) to (q are cross-sectional views of thermal conductivity detectors used in conventional gas chromatograph devices, respectively, and Figure 4 (
Al and (Bl is a front view showing one structural example of this invention and its 6 (5) and (B) are a front view and its X-
The X/cross-sectional view, FIGS. 7 and 8 are structural diagrams showing modifications thereof, respectively. 1... Board, 2... Thermocouple, 4... Terminal, 10
, 2ij...p-type semiconductor substrate, 11, 21...n
Mold region (Mt element), 12, 22A, 22B...
・Conductor, 14...Small hole, 15...Cavity, F, 27・
...Gas groove, 30...plate. Yuzo Yasugata, representative of the reactor, Figure 1
Figure 2 (A) Figure 4 Figure (,4) (B) Figure 5 Mouth (A) 〃 (β) Δ 12 t:y tt tu Figure #77 Figure 6 Figure 1127

Claims (1)

[Claims] A thermocouple comprising one or more n-type or p-type semiconductor regions formed in a single-crystal semiconductor substrate and a conductor deposited on both ends of the n-type or p-type regions, the thermocouple being interposed between the semiconductor region and the conductor. 1. A semiconductor thermocouple, characterized in that the temperature measuring junction of the thermocouple absorbs thermal energy to obtain a thermoelectromotive force.