Sensor with polycrystalline silicon resistors
First Claim
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1. Sensor with polycrystalline silicon resistors which are applied to a substrate and are covered with a dielectric passivating layer, in which temperature coefficients and resistance values of the resistors are adjusted and equalized by laser trimming, by doping the resistors and by healing with partial recrystallization of the resistors by laser healing with application of laser radiation or oven healing.
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Abstract
Sensor with polycrystalline silicon resistors which are applied to a substrate and are covered with a dielectric passivating layer, characterized by the feature that the resistors are thermally adapted by targeted adjustment of their dopings and by suitable healing, and are balanced by laser trimming.
66 Citations
23 Claims
- 1. Sensor with polycrystalline silicon resistors which are applied to a substrate and are covered with a dielectric passivating layer, in which temperature coefficients and resistance values of the resistors are adjusted and equalized by laser trimming, by doping the resistors and by healing with partial recrystallization of the resistors by laser healing with application of laser radiation or oven healing.
- 15. Sensor with polycrystalline silicon resistors which are applied to a substrate and are covered with a dielectric passivating layer, in which temperature coefficients and resistance values of the resistors are adjusted and equalized by laser trimming, by doping the resistors and by healing with partial recrystallization of the resistors by laser healing with application of laser radiation or oven healing, wherein the resistors are piezoresistive and are arranged in a bridge circuit, to form a pressure measuring device, wherein the resistors form additionally balancing resistors which have the same doping as the piezoresistive resistors to bring about compensation of the temperature coefficient of the bridge.
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21. Sensor with polycrystalline silicon resistors which are applied to a substrate and are covered with a dielectric passivating layer, in which temperature coefficients and resistance values of the resistors are adjusted and equalized by laser trimming, by doping the resistors and by healing with partial recrystallization of the resistors by laser healing with application of laser radiation or oven healing wherein the resistors are piezoresistive and are arranged in a bridge circuit, to form a pressure measuring device, wherein the piezoresistive resistors are doped to give a zero value temperature dependence of their sensitivity.
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22. Method for manufacturing a sensor with polycrystalline silicon resistors which comprises
(a) depositing a n-silicon layer epitaxially on an n+ -silicon substrate, (b) placing p-doped bridge resistors Rb which form the sensor, into the n-silicon layer by means of phototechniques, (c) applying a silicon dioxide layer to the entire semiconductor substrate over the entire surface, (d) reducing the applied silicon dioxide layer in the region of the bridge resistors (Rb) to a smaller layer thickness by means of a phototechnique, (e) thereupon, depositing a thin silicon nitride layer over the entire surface, (f) applying amorphous silicon to the silicon nitride layer over the entire surface, (g) doping parts of the applied amorphous silicon layer to obtain one and maximally two doping concentrations, (h) depositing a passivating layer in a predetermined layer thickness over the entire surface of the entire semiconductor wafer, (i) performing laser healing of certain regions of the amorphous silicon layer wherein the laser illuminates the regions line by line, (j) performing oven-healing of the entire semiconductor wafer, (k) structuring the amorphous silicon layer, whereby different polysilicon resistors (RK) and (RK'"'"') are formed, (l) performing a new passivation operation, (m) reducing the silicon substrate at the place of the bridge resistors (Rb) by means of etching on the back side, and (n) subjecting the polysilicon resistors (RK and RK'"'"') to a fine adjustment by means of laser trimming.
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23. Method for manufacturing a sensor with polycrystalline silicon resistors which comprises
(a) depositing a n-silicon layer epitaxially on an n+ -silicon substrate, (b) applying a silicon dioxide layer to the entire semiconductor substrate over the entire surface, (c) optionally, depositing a thin silicon nitride layer thereon over the entire surface, (d) applying amorphous silicon over the entire surface on the silicon nitride layer or silicon oxide layer, (e) doping parts of the applied amorphous silicon layer to obtain one and maximally two different doping concentration, (f) subsequently, performing laser healing of regions of the amorphous silicon layer wherein the laser illuminates the regions line by line, (g) performing oven-heating of the entire semiconductor wafer, (h) structuring the amorphous silicon layer, whereby different polysilicon resistors together with the bridge resistors are produced as pressure sensors, (i) performing a new passivation operation, (j) reducing the thickness of the substrate layer at the location of the bridge resistors (Rb) by means of etching on the back side, and (k) subjecting the polycrystalline silicon resistors to a fine adjustment by means of laser trimming.
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