Photoelectric converter

Claim 2

A photoelectric converter comprising a photosensor element, said photosensor element comprising: a transistor including a first semiconductor region having a first conductivity type, a second semiconductor region disposed contiguous to the first semiconductor region, the second semiconductor region having the same conductivity type as that of and a lower impurity concentration than that of the first semiconductor region, a third semiconductor region disposed contiguous to the second semiconductor region, the third semiconductor region having a different conductivity type from that of the second semiconductor region, a fourth semiconductor region disposed contiguous to the third semiconductor region, the fourth semiconductor region having a different conductivity type from that of the third semiconductor region, and a first electrode connected to the fourth semiconductor region; and a capacitor constituted by said third semiconductor region, an electrically insulating region disposed contiguous to the third semiconductor region, and a second electroce connected to the electrically insulating region; whereby said third semiconductor region is in a floating state so that the third semiconductor region is adapted for storing a charge generated by photoexcitation by controlling the potential of the third semiconductor region through said electrically insulating region, and an electric signal corresponding to the charge stored in the third semiconductor region is output from said first electrode.

Claim 3

The photoelectric converter according to claim 1, wherein a third electrode different from said second electrode is connected to said electrically insulating region.

Claim 4

The photoelectric converter according to claim 1 or 2, wherein said second semiconductor region is partially surrounded by a fifth semiconductor region, said fifth semiconductor region having the same conductivity type as that of and a higher impurity concentration than that of the second semiconductor region.

Claim 5

The photoelectric converter according to any of claims 1 to 4, wherein a sixth semiconductor region having the same conductivity type as that of said third semiconductor region is buried in said first semiconductor region.

Claim 6

The photoelectric converter according to any of claims 1 to 4, wherein a seventh semiconductor region having the same conductivity type as that of said third semiconductor region is disposed laterally from the third semiconductor region through said second semiconductor region.

Claim 7

The photoelectric converter according to any of claims 1 to 5, wherein a diode is connected to said third semiconductor region through a fourth electrode.

Claim 8

The photoelectric converter according to claim 6, wherein said diode is a pn junction diode.

Claim 9

The photoelectric converter according to any of claims 1 to 7, wherein said photosensor element further comprises an insulated-gate type transistor having a drain region constituted by said fourth semiconductor region.

Claim 10

The photoelectric converter according to any of claims 1 to 8, wherein said photosensor element further comprises a MOS transistor having a source region constituted by said third semiconductor region.

Claim 11

The photoelectric converter according to any of claims 1 to 9, wherein said fourth semiconductor region has a thickness in the depth direction of from 0.2 to 0.3 micron.

Claim 12

The photoelectric converter according to any of claims 1 to 10, wherein said fourth semiconductor region has an impurity concentration of 1 x 10 20 c m - 3 or above.

Claim 13

The photoelectric converter according to any of claims 1 to 11, wherein said fourth semiconductor region has a distribution of impurity concentration decreasing from the side of the light incidence surface toward the opposite side.

Claim 14

The photoelectric converter according to any of claims 1 to 12, wherein said third semiconductor region has a distribution of impurity concentration decreasing from the side of the light incidence surface toward the opposite side.

Claim 15

The photoelectric converter according to any of claims 1 to 13, wherein said fourth semiconductor region is grounded when the charge is stored in said third semiconductor region.

Claim 16

The photoelectric converter according to any of claims 1 to 14, wherein said fourth semiconductor region is floated when the charge is stored in said third semiconductor region.

Claim 17

The photoelectric converter according to any of claims 1 to 15, comprising a multiplicity of said photosensor elements disposed in a matrix of rows and columns in a semiconductor body.

Claim 18

A photoelectric converter comprising a photosensor element which in turn comprises a first transistor and a second transistor, said first transistor including a first semiconductor region, a third semiconductor region, a fourth semiconductor region and a high resistivity semiconductor region, and said second transistor including a second semiconductor region, said third semiconductor region, said fourth semiconductor region and said high resistance region, said first semiconductor region and said second semiconductor region having conductivity types different from each other, said third semiconductor region having a different conductivity type from that of the first semiconductor region and disposed contiguous to said first semiconductor region said fourth semiconductor region having a different conductivity type from that of the second semiconductor region and disposed contiguous to said second semiconductor reigon, said high resistivity semiconductor region being disposed between said third and fourth semiconductor regions and electrically connecting said third and fourth semiconductor regions, one of said third and fourth semiconductor regions functioning to store holes of electron-hole pairs generated by photo-excitation and the other to store electrons.

Claim 19

A photoelectric converter comprising a photosensor element which in turn comprises a first transistor and a second transistor, said first transistor including a first semiconductor region, a third semiconductor region, a fourth semiconductor region and a high resistivity semiconductor region, and said second transistor including a second semiconductor region, said third semiconductor region, said fourth semiconductor region and said high resistance region, said first semiconductor region and said second semiconductor region having conductivity types different from each other, said third semiconductor region having a different conductivity type from that of the first semiconductor region and disposed contiguous to said first semiconductor region said fourth semiconductor region having a different conductivity type from that of the second semiconductor region and disposed contiguous to said second semiconductor reigon, said high resistivity semiconductor region being disposed between said third and fourth semiconductor regions and electrically connecting said third and fourth semiconductor regions, one of said third and fourth semiconductor regions functioning to store holes of electron-hole pairs generated by photo-excitation and the other to store electrons.

Claim 20

The photoelectric converter according to claim 17, wherein said first semiconductor region has the conductivity type of n + , and said second semiconductor region has the conductivity type of p + .

Claim 21

The photoelectric converter according to claim 17 or 18, wherein said third semiconductor region has the conductivity type of p.

Claim 22

The photoelectric converter according to any of claims 17 to 19, wherein said high resistance semiconductor region is an n - region.

Claim 23

The photoelectric converter according to any of claims 17 to 20, wherein said photosensor element further compries an insulated-gate type transistor, said insulated-gate type transistor comprises: said third semiconductor region, a fifth semiconductor region having the same conductivity type as that of the third semiconductor region and disposed spaced apart from the third semiconductor region, a sixth semiconductor region disposed between the third and fifth semiconductor regions, having a different conductivity type from that of the third and fifth semiconductor region and electrically connecting the third and fifth semiconductor region, an electrically insulating region disposed on said sixth semiconductor region, and a first electrode disposed above said sixth semiconductor region through said electrically insulating region.

Claim 24

The photoelectric converter according to claim 21, wherein said first electrode extends above said third semiconductor region along with said electrically insulating layer so that it has a function of controlling the potential of the third semiconductor region.

Claim 25

The photoelectric converter according to claim 22, wherein the portions of the first electrode and the electrically insulating region extending above the third semiconductor region constitute a MOS capacitor in combination with the third semiconductor region below the first electrode.

Claim 26

The photoelectric converter according to any of claims 21 to 23, wherein said electrically insulating region extends above said fourth semiconductor region and a second electrode is disposed on the extending portion of the electrically insulating region.

Claim 27

The photoelectric converter according to claim 24, wherein the second electrode, the portion of the electrically insulating region extending above the fourth semiconductor region and the fourth semiconductor region below the second electrode, in combination, form a MOS capacitor.

Claim 28

The photoelectric converter according to any of claims 21 to 25, wherei said third, fifth and sixth semiconductor regions are all disposed in said high resistivity semiconductor region.

Claim 29

The photoelectric converter according to any of claims 17 to 26, wherein said high resistivity semiconductor region is dispod in said fourth semiconductor region.

Claim 30

The photoelectric converter according to any of claims 17 to 27, wherein said first semiconductor region is disposed in said third semiconductor region.

Claim 31

The photoelectric converter according to any of claims 24 to 28, wherein said second electrode has a function of controlling the potential of said fourth semiconductor region.

Claim 32

The photoelectric converter according to claims 17 to 29, wherein said photosensor element further comprises an insulating-gate type transistor connected to aid fourth semiconductor region.

Claim 33

The photoelectric converter according to claim 30, wherein said insulated-gate type transistor is an n-channel MOS transistor.

Claim 34

The photoelectric converter according to any of claims 17 to 31, comprising a multiplicity of said photosensor elements disposed in a matrix of rows and columns in a semiconductor body.

Claim 35

A photoelectric converter comprising a photosesor element, said photosensor element comprising: a first transistor including a first and a second semiconductor regions respectively having a first conductivity type, and a third semiconductor region having a second conductivity type opposite to the first conductivity type and being in a floating state; a second transistor including a fourth semiconductor region having said second conductivity type and directly connected to said third semiconductor region, a fifth semiconductor region having said second conductivity type, and a sixth semiconductor region having said first conductivity and being in a floatig state; and a first electrode connected to said sixth semiconductor region through an electrically insulating layer so as to control the potetial of the sixth semiconductor region.

Claim 36

A photoelectric converter comprising a photosesor element, said photosensor element comprising: a first transistor including a first and a second semiconductor regions respectively having a first conductivity type, and a third semiconductor region having a second conductivity type opposite to the first conductivity type and being in a floating state; a second transistor including a fourth semiconductor region having said second conductivity type and directly connected to said third semiconductor region, a fifth semiconductor region having said second conductivity type, and a sixth semiconductor region having said first conductivity and being in a floatig state; and a first electrode connected to said sixth semiconductor region through an electrically insulating layer so as to control the potetial of the sixth semiconductor region.

Claim 37

The photoelectric converter according to claim 33, wherien a first high resistivity semiconductor region is interposed between said first and third semiconductor regions.

Claim 38

The photoelectric converter according to claim 33 or 34, wherein a second high resistivity semiconductor region is interposed between said fourth and sixth semiconductor regions.

Claim 39

The photoelectric converter according to claim 35, wherein said second high resistivity semiconductor region is a region where charge carriers are generated through photo-excitation.

Claim 40

The photoelectric converter according to claim 36, wherein, of the charge carriers photo- generated in said second hig resistivity regions, one polarity of carriers are stored in said third semiconductor region and the other polarity of carriers are stored in said sixth semiconductor region.

Claim 41

The photoelectric converter according to any of Claims 1 to 16, wherein said fourth semiconductor region has the same conductivity type as that of said first semiconductor region.

Claim 42

The photoelectric converter according to any of Claims 1 to 16, wherein said fourth semiconductor region has a surface area smaller than that of said first semiconductor region.

Claim 43

The photoelectric converter according to any of Claims 1 to 16, wherein said fourth semiconductor region is highly doped.

Claim 44

The photoelectric converter according to any of Claims 1 to 16, wherein said fourth semiconductor region is a high resistivity semiconductor region.

Claim 45

A photoelectric conversion process comprising the steps of (A) providing a photoelectric converter comprising a transistor including a first semiconductor region having a first conductive type, a second semiconductor region disposed contiguous to the first semiconductor region, the second semiconductor region having the same conductivity type as that of and a lower impurity concentration than that of the first semiconductor region, a third semiconductor region disposed contiguous to the second semiconductor region, the third semiconductor region having a different conductivity type from that of the second semiconductor region, a fourth semiconductor region disposed contiguous to the third semiconductor region, the fourth semiconductor region having a different conductivity type from that of the third semiconductor region, and a first electrode connected to the fourth semiconductor region; and a capacitor constituted by said third semiconductor region, an electrically insulating region disposed contiguous to the third semiconductor region, and a second electroce connected to the electrically insulating region; and (B) sequentially and cyclically conducting the following stages of operations; (a) Charge Storage Operation, comprising setting the following initial conditions wherein; the first semiconductor region is held at a reverse polarity of voltage, the third semiconductor region is biased to a reverse polarity of volgage, and the fourth semiconductor region is grounded or, floated and illuminating the photosensor element with incident light to store a charge corresponding to the incident light in the third semiconductor region, (b) Readout Operation, comprising holding the fourth semiconductor region in a floating state and forward biasing the third semiconductor region to output an electrical signal corresponding to the charge in the third semicoductor region; and (c) Refreshing Operation, comprising holding the first semiconductor region at a ground potential or a reverse polarity of voltage, holdig the fourth semiconductor region at a ground potential, and applying a forward polarity of voltage to the third semiconductor region to remove a charge remaining corresponding to the photogenerated charge in the third semiconductor region.

Claim 46

A photoelectric conversion process comprising the steps of (A) providing a photoelectric converter comprising a transistor including a first semiconductor region having a first conductive type, a second semiconductor region disposed contiguous to the first semiconductor region, the second semiconductor region having the same conductivity type as that of and a lower impurity concentration than that of the first semiconductor region, a third semiconductor region disposed contiguous to the second semiconductor region, the third semiconductor region having a different conductivity type from that of the second semiconductor region, a fourth semiconductor region disposed contiguous to the third semiconductor region, the fourth semiconductor region having a different conductivity type from that of the third semiconductor region, and a first electrode connected to the fourth semiconductor region; and a capacitor constituted by said third semiconductor region, an electrically insulating region disposed contiguous to the third semiconductor region, and a second electroce connected to the electrically insulating region; and (B) sequentially and cyclically conducting the following stages of operations; (a) Charge Storage Operation, comprising setting the following initial conditions wherein; the first semiconductor region is held at a reverse polarity of voltage, the third semiconductor region is biased to a reverse polarity of volgage, and the fourth semiconductor region is grounded or, floated and illuminating the photosensor element with incident light to store a charge corresponding to the incident light in the third semiconductor region, (b) Readout Operation, comprising holding the fourth semiconductor region in a floating state and forward biasing the third semiconductor region to output an electrical signal corresponding to the charge in the third semicoductor region; and (c) Refreshing Operation, comprising holding the first semiconductor region at a ground potential or a reverse polarity of voltage, holdig the fourth semiconductor region at a ground potential, and applying a forward polarity of voltage to the third semiconductor region to remove a charge remaining corresponding to the photogenerated charge in the third semiconductor region.

Claim 47

A photoelectric converter comprising a photoresponsive transistor characterised in that photo- excited carriers are stored in a base region of said transistor, said base region being held in a floating ' state.

Claim 48

A photoelectric converter comprising a photoresponsive transistor characterised in that photo- excited carriers are stored in a base region of said transistor, said base region being held in a floating ' state.