Irreversible reduction of the value of a polycrystalline silicon resistor
View Patent ↗The invention relates to a method and device for the irreversible reduction of the value of an integrated polycrystalline silicon resistor. The inventive method consists in temporarily subjecting the resistor to a stress current which is greater than a current (Im) for which the value of the resistor is maximum.
1. A method for irreversibly decreasing a value of a resistance of an integrated polysilicon resistor, comprising temporarily submitting the resistor to a constraint current greater than a current for which the value of the resistance exhibits a maximum, the polysilicon resistor having a dopant concentration of polycrystalline silicon that is between approximately 1×10 13 atoms/cm 3 and approximately 1×10 16 atoms/cm 3 .
2. The method of claim 1 , wherein the constraint current to which the resistor is submitted is beyond an operating current range of an integrated circuit comprising the resistor.
3. The method of claim 1 , comprising the steps of:
increasing step by step the current in the resistor; and
measuring, after each application of a greater current, the value of the resistance in its normal functional environment.
4. The method of claim 1 , comprising using a predetermined table of correspondence between the constraint current and a desired final resistance to apply the constraint current to the resistor.
5. The method of claim 1 , wherein the constraint current is between approximately 1 mA and approximately 10 mA.
6. A device for irreversibly decreasing a resistance value of an integrated polysilicon resistor, comprising a circuit for temporarily imposing on the resistor a constraint current greater than a current value for which the value of the resistance exhibits a maximum, the polysilicon resistor having a dopant concentration of polycrystalline silicon that is between approximately 1×10 13 atoms/cm 3 and approximately 1×10 16 atoms/cm 3 .
7. The device of claim 6 , wherein the polysilicon resistor is connected to at least one switch of selection between an application circuit and a control circuit controlling a decrease in the resistance value.
8. The device of claim 7 , wherein the control circuit comprises a voltage source capable of being connected across the resistor, said voltage source being controllable by a circuit synchronizing a switching of said switch.
9. The device of claim 7 , wherein the control circuit comprises a current source capable of being connected in series with the resistor across two supply terminals, the current source being controllable by a circuit for synchronizing said switch.
10. The device of claim 6 , wherein the constraint current is between approximately 1 mA and approximately 10 mA.
11. The device of claim 6 , further comprising a control circuit constructed and arranged to impose a flowing of the constraint current greater than the current value for which the value of the resistance exhibits the maximum.
12. The device of claim 11 , further comprising an application circuit comprising said polysilicon resistor.
13. The device of claim 12 , further comprising a switch configured to switch between connecting the polysilicon resistor to the application circuit and connecting the polysilicon resistor to the control circuit.