US3890635A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable capacitance semiconductor devices
Assignee: General Electric Co
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Filing: 1973-12-26
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Granted: 1975-06-17
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Expires: 1993-12-26
Abstract
Abstract A high frequency CIS capacitance device having a substrate of one conductivity type provides a pair of values of capacitance for a high frequency signal applied across a pair of capacitance electrodes thereof. One of the values of capacitance is dependent on applying a control potential on a control electrode to the surface adjacent region underlying one of the capacitance electrodes through a channel region of opposite conductivity and greater in magnitude than the surface potential of the surface adjacent region to drain the surface adjacent region of charge carriers therein. Means are provided for alternatively establishing the channel region to produce one value of capacitance corresponding to depletion of charge carrriers from the surface adjacent region or another value of capacitance corresponding to establishing another value of surface potential in this surface adjacent region by other means. Such other means may be by applying another control potential through another channel region of opposite conductivity or by generation of charge carriers within the substrate. Composite devices are formed of elemental devices such as described in which the capacitance of the composite device is the sum of the capacitance of the elemental devices and is variable in discrete increments to provide a large number of discrete values of capacitance in response to digital signals applied to a minimum number of control electrodes connected thereto.
Inventors
- 👤 William E Engeler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 00:26
CPC Classifications
H; H10; H10D; H10D1/00; H10D1/60; H10D1/62; H10D1/66; H10D84/00; H10D84/80; H10D84/82; H10D84/83; H10D84/8311; H10D99/00; H10D84/83138
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
401 words
Semiconductor apparatus for providing a capacitance for a high frequency signal variable in discrete increments comprising a substrate of semiconductor material of one type conductivity, a plurality of capacitance providing electrodes, each insulatingly overlying and spaced a predetermined distance from a respective surface adjacent region of said substrate and forming with respect to a common electrode connected to said substrate a respective capacitor, said capacitance providing electrodes being connected together to provide a common capacitance providing electrode of said apparatus, means for applying a depletion producing voltage between said common capacitance providing electrode and said common electrode corresponding to a predetermined surface potential of said surface adjacent regions, said predetermined surface potential having an absolute value less than the absolute value of said depletion producing voltage and greater than the inversion threshold surface potential of said capacitors, means for applying a high frequency signal between said common capacitance providing electrode and said common electrode, control means for establishing individually in each of said surface adjacent regions a first potential in relation to said substrate corresponding to a respective low value of capacitance between a respective capacitance providing electrode and said common electrode, and for establishing alternatively and individually in each of said surface adjacent regions a second potential in relation to said substrate corresponding to a respective high value of capacitance between a respective capacitance providing electrode and said common electrode, said control means including a first control electrode, channel establishing means for individually establishing a plurality of first channel regions of opposite type conductivity in said substrate, each first channel region connected between a respective surface adjacent region and said first control electrode, and means for applying a first control potential to said first control electrode greater in magnitude than said predetermined surface potential whereby each surface adjacent region is drained of charge carries therein when a respective first channel is established, whereby the capacitance of said device is variable in increments dependent on the particular potentials established in the surface adjacent regions of the capacitors from a minimum value corresponding to the sum of the low value capacitances of the capacitors when said first potential is established in all of the surface adjacent regions of said capacitors to a maximum value corresponding to the sum of the high value capacitances of the capacitors when said second potential is established in all of said surface adjacent regions of said capacitors.
Claim 2
Dependent Claim
401 words
Semiconductor apparatus for providing a capacitance for a high frequency signal variable in discrete increments comprising a substrate of semiconductor material of one type conductivity, a plurality of capacitance providing electrodes, each insulatingly overlying and spaced a predetermined distance from a respective surface adjacent region of said substrate and forming with respect to a common electrode connected to said substrate a respective capacitor, said capacitance providing electrodes being connected together to provide a common capacitance providing electrode of said apparatus, means for applying a depletion producing voltage between said common capacitance providing electrode and said common electrode corresponding to a predetermined surface potential of said surface adjacent regions, said predetermined surface potential having an absolute value less than the absolute value of said depletion producing voltage and greater than the inversion threshold surface potential of said capacitors, means for applying a high frequency signal between said common capacitance providing electrode and said common electrode, control means for establishing individually in each of said surface adjacent regions a first potential in relation to said substrate corresponding to a respective low value of capacitance between a respective capacitance providing electrode and said common electrode, and for establishing alternatively and individually in each of said surface adjacent regions a second potential in relation to said substrate corresponding to a respective high value of capacitance between a respective capacitance providing electrode and said common electrode, said control means including a first control electrode, channel establishing means for individually establishing a plurality of first channel regions of opposite type conductivity in said substrate, each first channel region connected between a respective surface adjacent region and said first control electrode, and means for applying a first control potential to said first control electrode greater in magnitude than said predetermined surface potential whereby each surface adjacent region is drained of charge carries therein when a respective first channel is established, whereby the capacitance of said device is variable in increments dependent on the particular potentials established in the surface adjacent regions of the capacitors from a minimum value corresponding to the sum of the low value capacitances of the capacitors when said first potential is established in all of the surface adjacent regions of said capacitors to a maximum value corresponding to the sum of the high value capacitances of the capacitors when said second potential is established in all of said surface adjacent regions of said capacitors.
Claim 3
Dependent Claim
45 words
The combination of claim 1 in which said channel establishing means comprises a plurality of first gate electordes, each spaced in insulated relationship to said substrate to provide a respective first channel region when energized, means for individually energizing each of said first gate electrodes.
Claim 4
Dependent Claim
111 words
The combination of claim 1 in which is provided a second control electrode and means for producing a plurality of second channel regions of opposite conductivity in said substrate, each connected between said second control electrode and a respective surface adjacent region, the time constant of the capacitance of each of said surface adjacent regions and the resistance of the second channel region connected thereto from said second electrode being large in relation to a period of said high frequency signal, means for applying a potential to said second control electrode which establishes said second potential in each of said surface adjacent regions when a respective second channel region is established.
Claim 5
Dependent Claim
127 words
The combination of claim 1 in which is provided a second control electrode and means for producing a plurality of second channel regions of opposite conductivity in said substrate, each connected between said second control electrode and a respective surface adjacent region, the time constant of the capacitance of each of said surface adjacent regions and the resistance of the second channel region connected thereto from said second electrode being large in relation to a period of said high frequency signal, means for providing a potential to said first control electrode greater than said predetermined surface potential of said capacitors and for providing said second potential to said second control electrode, means for alternatively establishing the first channel region connected to each of said surface adjacent regions.
Claim 6
Dependent Claim
29 words
The combination of claim 4 in which the end of each of said first channel regions remote from said first electrode are connected to a respective second channel region.
Claim 7
Dependent Claim
74 words
The combination of claim 5 in which the impedance of each of the established second channel regions between said second electrode and point of connection of a respective first channel region thereto is large in relation to the impedance of said respective first channel region whereby when of each said first channel regions are established a potential greater than said predetermined surface potential is applied to the surface adjacent region of a respective capacitor.
Claim 8
Dependent Claim
17 words
The combination of claim 4 in which said second potential is substantially the potential of said substrate.
Claim 9
Dependent Claim
32 words
The combination of claim 4 in which the end of each of said first channel regions remote from said first electrode are connected between the ends of a respective second channel region.
Claim 10
Dependent Claim
71 words
The combination of claim 4 in which each of said first channel regions is the channel of a respective MOSFET transistor formed in said substrate and including a source, a drain and a gate electrode with each source connected to a respective surface adjacent region and each drain connected to said first control electrode, and means for energizing each of said gate electrodes for establishing a channel in a respective transistor.
Claim 11
Dependent Claim
171 words
The combination of claim 4 in which each of said first channel regions is the channel of a respective first MOSFET transistor formed in said substrate and including a first source electrode, a first drain electrode and a first gate electrode and in which each of said second channel regions is the channel of a respective second MOSFET transistor formed in said substrate and including a second source electrode, a second drain electrode, and a second gate electrode, each of said second source electrodes being connected to said second control electrode, each of said second drain electrodes being connected to a respective surface adjacent region, each of said first source electrodes connected to a point on the channel of a respective second MOSFET transistor intermediate the ends thereof, each of said second drain electrodes connected to a respective second gate electrode and a potential greater than said predetermined surface potential of said capacitors, and means for energizing each of said first gate electrodes for estaBlishing a channel in a respective transistor.
Claim 12
Dependent Claim
258 words
A semiconductor device for providing a pair of discrete values of capacitance for a high frequency signal comprising a body of semiconductor material of one type conductivity, a first conductive member insulatingly overlying a surface adjacent region of said body, a second conductive member in electrical contact with another region of said device, means for applying a depletion producing voltage between said first and second conductive members corresponding to a predetermined surface potential of said surface adjacent region, said predetermined surface potential having an absolute value less than said depletion producing voltage but greater than the inversion threshold voltage of said device, a first control electrode for controlling the capacitance between said first and second conductive members, means for applying a first control potential to said first control electrode greater in magnitude than said predetermined surface potential, a first biasing means for selectively providing a first channel region of opposite type conductivity between said first control electrode and said first surface adjacent region, a second control electrode for controlling the capacitance between said first and second conductive members, a second biasing means for selectively establishing a second channel region of opposite type conductivity connected between said second control electrode and said surface adjacent region, the time constant of the capacitance of said surface adjacent region and the resistance of said second channel region being large in relation to a period of said high frequency signal, means for alternatley rendering operative said first and second biasing means to establish one or the other of said discrete values of capacitance.
Claim 13
Dependent Claim
258 words
A semiconductor device for providing a pair of discrete values of capacitance for a high frequency signal comprising a body of semiconductor material of one type conductivity, a first conductive member insulatingly overlying a surface adjacent region of said body, a second conductive member in electrical contact with another region of said device, means for applying a depletion producing voltage between said first and second conductive members corresponding to a predetermined surface potential of said surface adjacent region, said predetermined surface potential having an absolute value less than said depletion producing voltage but greater than the inversion threshold voltage of said device, a first control electrode for controlling the capacitance between said first and second conductive members, means for applying a first control potential to said first control electrode greater in magnitude than said predetermined surface potential, a first biasing means for selectively providing a first channel region of opposite type conductivity between said first control electrode and said first surface adjacent region, a second control electrode for controlling the capacitance between said first and second conductive members, a second biasing means for selectively establishing a second channel region of opposite type conductivity connected between said second control electrode and said surface adjacent region, the time constant of the capacitance of said surface adjacent region and the resistance of said second channel region being large in relation to a period of said high frequency signal, means for alternatley rendering operative said first and second biasing means to establish one or the other of said discrete values of capacitance.
Claim 14
Dependent Claim
110 words
The combination of claim 11 in which said first biasing means includes a pair of activator induced surface adjacent regions of opposite conductivity type spaced apart to form a surface channel therebetween, one of said pair of regions of opposite conductivity type contacting said first surface adjacent region and the other of said pair of regions of opposite conductivity type connected to a source of bias potential providing a potential greater than said predetermined surface potential, and voltage means for rendering said surface channel opposite in conductivity type to said one conductivity type thereby lowering the potential of said surface adjacent region to a value below said predetermined surface potential.
Claim 15
Dependent Claim
27 words
The combination of claim 12 in which said first channel region and said second channel region are connected to a common portion of said surface adjacent region.
Claim 16
Dependent Claim
25 words
The combination of claim 13 in which the impedance of said first channel region is substantially greater than the impedance of said second channel region.
Claim 17
Dependent Claim
23 words
The combination of claim 14 in which said first channel region is continuously maintained and in which said second channel is selectively established.
Claim 18
Dependent Claim
36 words
The combination of claim 15 in which said second channel region includes a high impedance portion and a low impedance portion and in which said first channel region is connected to the juncture of said portions.
Claim 19
Dependent Claim
189 words
A semiconductor device for providing a pair of discrete values of capacitance for a high frequency signal comprising a body of semiconductor material of one type conductivity, a first conductive member insulatingly overlying a surface adjacent region of said body, a second conductive member in electrical contact with another region of said device, means for applying a depletion producing voltage between said first and second conductive members to a predetermined surface, potential of said corresponding surface adjacent region, said predetermined surface potential having an absolute value less than the absolute value of said depletion producing voltage and greater than the inversion threshold voltage of said devicE, a first biasing means for selectively applying a voltage to said first surface adjacent region greater than said predetermined surface potential, whereby when said voltage is applied to said first surface adjacent region the capacitance between said first and second conductive members has one of said pair of values and when no voltage is applied an inversion layer is established in said surface adjacent region and the capacitance between said first and second conductive members has another value greater than said one value.
Claim 20
Dependent Claim
189 words
A semiconductor device for providing a pair of discrete values of capacitance for a high frequency signal comprising a body of semiconductor material of one type conductivity, a first conductive member insulatingly overlying a surface adjacent region of said body, a second conductive member in electrical contact with another region of said device, means for applying a depletion producing voltage between said first and second conductive members to a predetermined surface, potential of said corresponding surface adjacent region, said predetermined surface potential having an absolute value less than the absolute value of said depletion producing voltage and greater than the inversion threshold voltage of said devicE, a first biasing means for selectively applying a voltage to said first surface adjacent region greater than said predetermined surface potential, whereby when said voltage is applied to said first surface adjacent region the capacitance between said first and second conductive members has one of said pair of values and when no voltage is applied an inversion layer is established in said surface adjacent region and the capacitance between said first and second conductive members has another value greater than said one value.
Claim 21
Dependent Claim
109 words
The combination of claim 16 in which said first biasing means includes a pair of activator induced surface adjacent regions of opposite conductivity type spaced apart to form a surface channel therebetween, one of said pair of regions of opposite conductivity type contacting said surface adjacent region and the other of said pair of regions of opposite conductivity type connected to a source of bias potential providing a potential greater than said predetermined surface potential, and voltage means for rendering said surface channel opposite in conductivity type to said one conductivity type thereby lowering the potential of said surface adjacent region to a value below said predetermined surface potential.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-06-16 | 1978-12-16 | 1979-06-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-16 | 1982-12-16 | 1983-06-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-16 | 1986-12-16 | 1987-06-17 | $7700.00 | Window Closed / Lapsed |