Method of forming a semiconductor device
In one embodiment, a method of forming a semiconductor device may include forming a sense resistor to receive a high voltage signal and form a sense signal that is representative of the high voltage signal. An embodiment of the sense resistor may optionally be formed overlying a polysilicon resistor. The method may also have an embodiment that may include forming a plurality of capacitors in parallel to portions of the sense resistor wherein the plurality of capacitors are connected together in series.
1. A circuit for sensing a high voltage comprising:
a semiconductor substrate;
a doped region on the semiconductor substrate;
a polysilicon resistor formed in a pattern overlying the doped region;
a plurality of first insulator layers overlying the polysilicon resistor, each first insulator layer having an interconnect conductor formed thereon;
a silicon-chrome resistor having a length and formed overlying the plurality of first insulator layers, the silicon-chrome resistor overlying the polysilicon resistor and formed in substantially the pattern;
a second insulator on the silicon-chrome resistor including on sides of the silicon-chrome resistor;
a plurality of metal-insulator-metal capacitors on the second insulator and overlying at least a part of the silicon-chrome resistor, each metal-insulator-metal capacitor connected in parallel with portions of the silicon-chrome resistor, a first metal-insulator-metal capacitor of the plurality of metal-insulator-metal capacitors including a first metal layer spaced a distance apart from a second metal layer with a first portion of a third insulator between the first metal layer and the second metal layer;
the first metal layer connected at a first point along the length of the silicon-chrome resistor;
the second metal layer connected at a second point along the length of the silicon-chrome resistor; and
a third point along the length of the silicon-chrome resistor configured to form an output signal.
2. The circuit of claim 1 wherein the pattern is a spiral.
3. The circuit of claim 2 wherein the first metal layer is formed as a circle having a first radius from a center of the spiral and the second metal layer is formed a second circle having a second radius from the center of the spiral wherein the second radius is different from the first radius.
4. The circuit of claim 1 wherein a first terminal of the silicon-chrome resistor is configured to receive a high voltage signal.
5. The circuit of claim 1 wherein the third insulator is on the first metal layer and on the second metal layer.
6. The circuit of claim 1 further including a second metal-insulator-metal capacitor of the plurality of metal-insulator-metal capacitors, the second metal-insulator-metal capacitor including a third metal layer spaced the distance apart from the second metal layer with a second portion of the third insulator between the third metal layer and the second metal layer.
7. The circuit of claim 1 wherein the first metal layer has a first plurality of fingers extending from the first metal layer toward the second metal layer.
8. The circuit of claim 7 wherein the second metal layer has a second plurality of fingers extending from the second metal layer toward the first metal layer wherein the second plurality of fingers is inter-digitized with the first plurality of fingers.
9. The circuit of claim 1 wherein the plurality of first insulator layers includes at least three insulator layers.
10. The circuit of claim 1 wherein the doped region is a portion of a junction field effect transistor.
11. A circuit for high voltage sensing, the circuit comprising:
a semiconductor substrate;
a doped region on the semiconductor substrate wherein the doped region is a portion of a field effect transistor;
a polysilicon resistor formed in a pattern overlying the doped region;
a plurality of first insulator layers overlying the polysilicon resistor;
an interconnect conductor formed on one or more of the plurality of first insulator layers;
a resistor formed in substantially the pattern, the resistor overlying the plurality of first insulator layers and at least a portion of the polysilicon resistor;
a second insulator layer formed on the resistor;
a first metal layer on the second insulator layer and extending in a direction across the second insulator layer, the first metal layer connected to a first part of the resistor;
a second metal layer on the second insulator layer and spaced a distance from the first metal layer to form a first space therebetween, the second metal layer extending in the direction across the second insulator layer, the second metal layer connected to a second part of the resistor;
a third insulator having a first portion in the first space; and
an output connected to a third part of the resistor, the output configured to form a sense signal.
12. The circuit of claim 11 wherein the resistor is formed from one of titanium nitride, tantalum nitride, a silicon-chrome alloy, a nickel-chrome alloy, or a silicon-chrome-carbon alloy.
13. The circuit of claim 11 wherein the polysilicon resistor does not form an output signal.
14. The circuit of claim 11 wherein the resistor has a first terminal configured to receive a high voltage and to form a signal representative of the high voltage on the output.
15. The circuit of claim 14 wherein a drain of the field effect transistor is coupled to a first terminal of the resistor and to receive the high voltage.
16. The circuit of claim 11 wherein the first metal layer, the second metal layer, and the first portion of the third insulator form a capacitor connected in parallel to a portion of the resistor.
17. The circuit of claim 11 further including a third metal layer on the second insulator layer and extending in the direction across the second insulator layer, the third metal layer spaced apart from the second metal layer to form a second space therebetween, a third portion of the third insulator in the second space, the third metal layer connected to a fourth part of the resistor wherein the second metal layer, the third metal layer, and the third portion of third insulator form a capacitor connected in parallel with a portion of the resistor.
18. A method of forming a semiconductor device comprising:
forming a sense resistor to receive a high voltage signal and form a sense signal that is representative of the high voltage signal;
forming a plurality of first insulator layers underlying the sense resistor overlying a semiconductor substrate; and
forming a plurality of capacitors in parallel to portions of the sense resistor wherein the plurality of capacitors is connected together in series.
19. The method of claim 18 further including forming a polysilicon resistor overlying an active region of a transistor wherein the polysilicon resistor receives the high voltage signal but does not form an output signal that is representative of the high voltage signal.
20. The method of claim 18 including forming the sense resistor on a second insulator that is overlying the plurality of first insulator layers and forming the plurality of capacitors one of overlying sections of the sense resistor or on the second insulator spaced laterally from the sense resistor.