High voltage sensor device and method therefor
View Patent ↗In one embodiment, a high voltage element is formed overlying a doped semiconductor region that can be depleted during the operation of the high voltage element.
1. A method of forming a high voltage sensing element comprising:
providing a substrate of a first semiconductor material having a first conductivity type;
forming a first doped region of a second conductivity type on a first portion of the substrate including forming the first doped region to operably receive an input voltage;
forming an MOS transistor;
forming an insulator overlying a portion of the first doped region wherein the insulator has a first thickness that is greater than a second thickness of a gate insulator of the MOS transistor; and
forming a first resistor overlying the insulator wherein a first terminal of the first resistor is coupled to the first doped region.
2. The method of claim 1 further including electrically coupling a first terminal of the first resistor to the substrate.
3. The method of claim 2 wherein electrically coupling the first terminal of the first resistor to the substrate includes coupling a switch between the first terminal of the first resistor and the substrate in order to couple the first terminal to the substrate.
4. The method of claim 1 further including forming a second resistor overlying the insulator and coupling a first terminal of the second resistor to a second terminal of the first resistor at a common node.
5. The method of claim 4 wherein forming the second resistor includes coupling the common node to another electrical element that is formed on the substrate.
6. The method of claim 1 wherein forming the insulator overlying the first doped region includes forming the gate insulator to be no greater than about two hundred nano meters.
7. The method of claim 1 wherein forming the insulator overlying the first doped region includes forming the first thickness about two to one hundred times greater than the second thickness.
8. The method of claim 1 wherein forming the first doped region includes forming the first doped region with a non-graded doping profile.
9. The method of claim 1 wherein forming the first resistor includes coupling a second terminal of the first resistor to an input of a current mirror.
10. The method of claim 1 wherein forming the first doped region includes forming a first portion of the first doped region as a channel region of a J-FET.
11. The method of claim 10 wherein forming the first doped region includes forming a second portion of the first doped region as a drain region of the MOS transistor.
12. A method of forming a high voltage element of a semiconductor device comprising:
providing a substrate of a first semiconductor material having a first conductivity type;
forming a first doped region of a second conductivity type on a first portion of the substrate;
forming an insulator overlying at least a portion of the first doped region wherein the insulator has a first thickness;
forming a first resistor overlying the insulator;
coupling a first terminal of the first resistor to receive a signal representative of a signal applied to the first doped region; and
coupling a second terminal of the first resistor to a circuit external to the high voltage element and not connected directly to the high voltage element.
13. The method of claim 12 wherein coupling the first terminal of the first resistor to receive the signal representative of the signal applied to the first doped region includes coupling the first terminal of the first resistor to receive a high voltage that is greater than five volts.
14. The method of claim 12 further including forming a second resistor and coupling a first terminal of the second resistor to the first terminal of the first resistor.
15. The method of claim 14 further including coupling a second terminal of the second resistor to the substrate externally to the high voltage element.
16. The method of claim 12 wherein forming the first doped region includes forming the first doped region having a non-graded doping profile.
17. The method of claim 12 wherein forming the first doped region includes forming a portion of the first doped region as a current carrying electrode of a transistor wherein the second terminal of the first resistor is not coupled to either a current carrying electrode or a control electrode of the transistor.
18. A method of forming a high voltage element of a semiconductor device comprising:
providing a substrate of a first semiconductor material having a first conductivity type;
forming a first doped region of a second conductivity type on a first portion of the substrate;
forming an insulator overlying at least a portion of the first doped region wherein the insulator has a first thickness;
forming a first resistor of overlying at least a first portion of the insulator; and
coupling a first terminal of the first resistor to the substrate.
19. The method of claim 18 further including coupling a second terminal of the first resistor to a second resistor of a resistor divider wherein the second resistor is overlying at least a second portion of the insulator.
20. The method of claim 18 including forming the insulator having a thickness that is greater than a thickness of a gate insulator of an MOS transistor that is formed on the substrate.
21. A method of forming a high voltage element of a semiconductor device comprising:
providing a substrate of a first semiconductor material having a first conductivity type;
forming a transistor on a first portion of the substrate;
forming an insulator overlying at least a first portion of an active region of the transistor; and
forming a first resistor overlying at least a first portion of the active region of the transistor and overlying the insulator wherein a first terminal of the first resistor is not coupled to the transistor.
22. The method of claim 21 wherein forming the transistor includes forming a J-FET.