Field-effect photo-transistor

A high output impedance, three-terminal photosensing electrical device (e.g., 80A, 80B) integrated on a semiconductor substrate, the photosensing electrical device having a body terminal, a gate terminal, and a drain terminal, the body terminal being an electrical contact to the semiconductor substrate bulk, and the photosensing electrical device comprising:

• (a) a four-terminal MOSFET having a body terminal, a source terminal, a gate terminal, and a drain terminal, wherein:
• if the semiconductor substrate is p type, then the MOSFET is n-channel type;
• and
• if the semiconductor substrate is n type, then the MOSFET is p-channel type;
• and
• (b) an MOS photogate, comprising:
• (1) an MOS photo-capacitor sub-structure having a substrate side and a field-plate side, wherein:
• the dielectric medium is a thin (gate) dielectric layer;
• the substrate side is the semiconductor substrate bulk;
• the field plate side is a conducting thin-film layer;
• and
• the combination of thin dielectric layer and conducting thin-film layer are adequately transparent to a target portion of incident-light spectrum;
• and
• (2) a junction-diode sub-structure having an anode side and a cathode side, wherein:
• if the semiconductor substrate is p type, then the anode side is the semiconductor substrate bulk and the cathode side is an n-type feature diffused into the semiconductor substrate;
• if the semiconductor substrate is n type, then the cathode side is the semiconductor substrate bulk and the anode side is a p-type feature diffused into the semiconductor substrate, wherein:
• the diffused side of the junction-diode sub-structure abuts the photo-capacitor sub-structure such that the space-charge region of the junction-diode sub-structure and the space-charge region, forming in the semiconductor substrate side of the photo-capacitor sub-structure when the photo-capacitor is biased into inversion or depletion, merge into one contiguous space-charge region;
• the body of the MOSFET is electrically connected to the semiconductor substrate bulk;
• the source terminal of the MOSFET is electrically connected to the diffused side of the junction diode sub-structure;
• the gate terminal of the MOSFET is electrically connected to the field plate side the photo-capacitor sub-structure;
• the drain terminal of the MOSFET is the drain terminal of the photosensing electrical device;
• and
• the gate terminal of the MOSFET is the gate terminal of the photosensing electrical device.

A high output impedance, three-terminal, photosensing electrical device (e.g., 150) integrated on a semiconductor substrate, the photosensing electrical device having a body terminal, a gate terminal, and a drain terminal, the body terminal being an electrical contact to the semiconductor substrate bulk, and the photosensing electrical device comprising:

• (a) an MOS photo-capacitor sub-structure having a semiconductor substrate side and a field-plate side, wherein:
• the dielectric medium is a thin (gate) dielectric layer;
• the substrate side is the semiconductor substrate bulk;
• the field plate side is a conducting thin-film layer;
• and
• the combination of thin dielectric layer and conducting thin-film layer are adequately transparent to a target portion of incident-light spectrum;
• and
• (b) a junction-diode sub-structure having an anode side and a cathode side, wherein:
• if the semiconductor substrate is p type, then the anode side is the semiconductor substrate bulk and the cathode side is an n-type feature diffused into the semiconductor substrate;
• if the semiconductor substrate is n type, then the cathode side is the semiconductor substrate bulk and the anode side is a p-type feature diffused into the semiconductor substrate;
• the gate terminal of the photosensing electrical device is an electrical contact to the field plate of the photo-capacitor sub-structure;
• the drain terminal of the photosensing electrical device is an electrical contact to the diffused side of the junction-diode sub-structure;
• the diffused side of the junction-diode sub-structure abuts the photo-capacitor sub-structure such that the space-charge region of the junction-diode sub-structure and the space-charge region, forming in the semiconductor substrate side of the photo-capacitor sub-structure when the photo-capacitor is biased into inversion or depletion, merge into one contiguous space-charge region;
• the photo-capacitor sub-structure is divided into two regions, each inverting at a different threshold voltage;
• if the semiconductor substrate is p-type, then the junction-diode sub-structure abuts only the region of the photo-capacitor sub-structure with the (algebraically) higher threshold voltage;
• and
• if the semiconductor substrate is n-type, then the junction-diode sub-structure abuts only the region of the photo-capacitor sub-structure with the (algebraically) lower threshold voltage.

A high output impedance, three-terminal, photosensing electrical device (e.g., 160A, 160B) integrated on a semiconductor substrate, the photosensing electrical device having a body terminal, a gate terminal, and a drain terminal, the body terminal being an electrical contact to the semiconductor substrate bulk, and the photosensing electrical device comprising:

• (a) an MOS photo-capacitor sub-structure having a semiconductor substrate side and a field-plate side, wherein:
• the dielectric medium is a thin (gate) dielectric layer;
• the substrate side is the semiconductor substrate bulk;
• the field-plate side is a conducting thin-film layer;
• and
• the combination of thin dielectric layer and conducting thin-film layer are adequately transparent to a target portion of incident-light spectrum;
• and
• (b) a junction-diode sub-structure having an anode side and a cathode side, wherein:
• if the semiconductor substrate is p type, then the anode side is the semiconductor substrate bulk and the cathode side is an n-type feature diffused into the semiconductor substrate;
• if the semiconductor substrate is n type, then the cathode side is the semiconductor substrate bulk and the anode side is a p-type feature diffused into the semiconductor substrate;
• the gate terminal of the photosensing electrical device is an electrical contact to the field plate of the photo-capacitor sub-structure;
• the drain terminal of the photosensing electrical device is an electrical contact to the diffused side of the junction-diode sub-structure;
• the diffused side of the junction-diode sub-structure abuts the photo-capacitor sub-structure such that the space-charge region of the junction-diode sub-structure and the space-charge region, forming in the semiconductor substrate side of the photo-capacitor sub-structure when the photo-capacitor is biased into inversion or depletion, merge into one contiguous space-charge region;
• the photo-capacitor sub-structure is divided into one or more regions, each inverting at a different threshold voltage;
• if the semiconductor substrate is p-type, then the junction-diode sub-structure abuts only the region of the photo-capacitor sub-structure with the (algebraically) highest threshold voltage;
• and
• if the semiconductor substrate is n-type, then the junction-diode sub-structure abuts only the region of the photo-capacitor sub-structure with the (algebraically) lowest threshold voltage.