HU198338B - Method for making piezoresistive sensors - Google Patents

Abstract

Procedure for low temperature-dependent psoriasis - mainly for measuring force, pressure and acceleration - for the production of sensors during which the carrier is used We use n-type silicon semiconductor material, as an additive to the surface layer of the substrate as an ion implant boron, followed by a increasing the atoms of the additive from the surface layer , the carrier is deeper in the gas stream into the layer. Its characteristic is that for Implantation 20-30 ° C charge and 25-150 keV implantation we use energy boron. After implantation with the additive contaminated carrier 1000- Heat at an ambient temperature of 1100 ° C for heat treatment 50 to 240 µl per 100-200 Uter / hour volume flow Oj gas bath and optionally up to 180 minutes at a flow rate of 100-200 Hertz / hour We use N2 gas bath.

Description

FIELD OF THE INVENTION The present invention relates to a process for making low temperature dependence piezoresistive sensors, primarily for measuring force, pressure and acceleration, using a silicon semiconductor material of type n, boron ions as an additive to the surface layer of a carrier, and subsequently adding a temperature with the aid of a gas stream into the deeper layer of the substrate.

The diffusion process and the ion implantation technique used in the manufacture of new integrated circuits have gained great potential in the manufacture of various sensors.

Both solutions are known in the manufacture of piezoresistive sensors. A diffusion procedure is described in 4.065. U.S. Patent No. 971 and IEEE Trans.on Electron Devices ED. 26 No. 12.1979. December issue.

U.S. Pat. No. 4,129,042 discloses a semiconductor signal transducer in which a n-type silicon plate is contaminated with boron atoms in an amount of 10 ⁵ atoms / cm ^{2 to form} the pleistor resistor. The introduction of boron atoms was solved with a lonImplanter.

The large spread of semiconductor piezo-resistive sensors is explained by the fact that they have a higher sensitivity and lifetime, and that their nonlinearity and hysteresis are significantly lower than conventional sensors.

However, besides the good properties, the temperature dependence of the sensor conversion factor is a major problem. This temperature dependence depends on the manufacturing technology of the piezoresistive arc sensor, including the amount of additive introduced into the substrate and its depth distribution over the surface.

By the diffusion process, it is impossible to produce an additive distribution that would result in a temperature-independent but only slightly temperature-independent sensing device.

Piezoresistive sensors made with ion implantation show better results, but the procedure for providing accurate, controlled parameters has not yet become known.

The object of the present invention was to provide a piezo-resistive sensor for measuring pressure, force or acceleration with high sensitivity and lifetime, low non-linearity and hysteresis, but also exhibiting an absolute and standard deviation of temperature less than known solutions.

The process of the present invention has led to the discovery that a sensor resistor-temperature function can be generated as a function of the sensor conversion factor. If the resistance temperature generated is a function of the inverse of the conversion factor temperature, the output signal from the sensor will be nearly temperature independent.

Therefore, if the parameters of the known ion implantation procedure are properly selected and high temperature heat treatment is applied after implantation, the task can be accomplished.

According to an object of the invention, the method of the invention for producing low temperature dependence piezoresistive sensors, primarily for measuring force, pressure and acceleration, using n-type silicon semiconductor as carrier, boron ions are added to the surface layer of the carrier as an additive. of the additive atoms is introduced into the deeper layer of the substrate by means of a temperature increase in a gas stream, based on the use of a boron ion of charge 20-30 pC and an implantation energy of 25-150 keV, the substrate contaminated with the additive and an O ₂ gas bath of 100 to 200 Uter / hour for 60-240 minutes and optionally of 100 to 200 Uter / hour of N ₂ for up to 180 minutes we use a gas bath.

The invention may further feature that loniinplantáeíót note of 26 pC charge quantity of 11 B ⁺ source of energy 100 keV implant and the post-implantation heat treatment is carried out at 1050 C and the heat treatment for 100 minutes 160 liters, a volume flow of O ₂ gas, and 140 at 160 liters of N ₂ gas are used per hour.

A preferred method unchanged lonimplantációt energy of 50 keV and implantation is carried out 26 pC charge amount of the source 11B and the post-implantation heat treatment is 1050 ° C is carried out, the heat treatment for 100 minutes 160 liters / hour térfogataramu O ₂ gas, and 140 min to 160 l / h flow rate N ₂ gas is used.

The piezo-resistive sensors of the present invention have the advantage that the sensors have high sensitivity and long life.

They also have the advantage of small nonUnearity and hysteresis.

A further advantage is that they are able to realize these properties at low temperature dependence. The process results in well-controlled product properties, so that the degree of temperature dependence can be adjusted within strict tolerances.

The invention will now be described in more detail by way of example.

Example:

To produce a piezo-resistive sensor, boron ions were generated from source 11B in the lonimplant device. During implantation, p-type resistors were formed in the type silicon semiconductor plate as a carrier with 26 pC charge and 100 keV implantation energy.

Following ion implantation, the substrate contaminated with boron ions was subjected to heat treatment.

The heat treatment was carried out at 1050 ° C. The heat treatment is used 160 l / h of O ₂ gas flow and the same flow of N ₂ gas. The gas stream 0 _{2 was} allowed to flow into the treatment room containing the contaminated carrier for 100 minutes and the gas flow to N _{2 for} 140 minutes.

At the end of the process, a low temperature-dependent pressure sensor was obtained.

Piezoresistive sensors made by the method of the present invention are well suited for measuring force, pressure or acceleration at locations where accurate measurement results independent of temperature are required.

Claims (3)

Claims 1. A method for producing low temperature dependent pleoresistive sensors, primarily for the measurement of force, pressure and acceleration using a silicon semiconductor material of type n, boronons as an additive to the surface layer of the support, followed by addition of a temperature atom to the surface layer. with a charge of 20 to 30 pC and an implant energy of 25 to 150 keV, the substrate contaminated with the additive is heat-treated at ambient temperature of 1000 to 1100 ° C and 60 240 for heat treatment. an O ₂ gas bath with a flow rate of 100 200 Uter / h and an N ₂ gas bath with a flow rate of 100 200 l / h for a maximum of 180 minutes, 2. The method according to claim 1, characterized in that the lonimplantádót performed 26 pC charge quantity 11 source B 100 keV implantation energy and the implantation, heat treatment is carried out at 1050 C and the heat treatment of 100 minutes at flow 160 Uter / hr O ₂ gas and 160 liters / hour of N ₂ gas for 140 minutes. The method of claim 1, wherein the Jonl implantation is performed from 11 B ** sources with an implant energy of 50 keV at a charge of 26 pC, and the post-implant heat treatment is performed at 1050 C for 100 minutes at a flow rate of 160 Uter / h. N ₂ gas is used.