Photo detector and methods of manufacturing and operating same

A monolithic photo detector disposed in a substrate, the monolithic photo detector comprising:

• a doped impurity region disposed in the substrate or on a major surface of the substrate;
• a gate disposed over and spaced from the major surface of the substrate with an insulator and laterally disposed apart from and on a first side of the doped impurity region;
• a contact region, disposed in the substrate or on the major surface of the substrate and laterally disposed apart from and on the first side of the doped impurity region further removed from the first side of the doped impurity region than the gate;
• and
• a light absorbing region disposed in the substrate or on the major surface of the substrate and laterally disposed apart from and on the first side of the doped impurity region between the gate and the contact region, wherein the light absorbing region includes at least one material in which, in response to light incident thereon, carrier pairs of opposite charge are generated, each carrier pair including a first type carrier and a second type carrier;
• wherein, in response to light incident on the light absorbing region,
• the gate attracts first type carriers of the carrier pairs which, in response, causes second type carriers from the doped impurity region to flow through the light absorbing region to the contact region, and
• the contact region attracts second type carriers of the carrier pairs;
• wherein a flow of the first type carriers and second type carriers of the carrier pairs is delayed and a start of the flow of the first type carriers and second type carriers of the carrier pairs is inversely proportional to an intensity of light incident on the light absorbing region.

A monolithic photo detector device comprising:

• a bulk substrate;
• and
• a photo detector disposed in the bulk substrate or on the bulk substrate including:
• a doped impurity region disposed in the bulk substrate or on a major surface of the bulk substrate and extending in a first direction over the major surface of the bulk substrate;
• a gate including a first gate portion and a second gate portion, each gate portion being (i) spaced apart from the other and (ii) spaced from and extending in the first direction over the major surface of the bulk substrate, wherein the doped impurity region is laterally disposed between the first and second gate portions along the first direction;
• a contact region, disposed in or on the major surface of the bulk substrate;
• and
• a light absorbing region disposed in or on the major surface of the bulk substrate, wherein the light absorbing region includes at least one material in which, in response to light incident thereon, carrier pairs are generated, each carrier pair including a first type carrier and a second type carrier, and wherein the light absorbing region is laterally disposed between the contact region and the first gate portion of the gate;
• wherein, in response to light incident on the light absorbing region, the gate attracts first type carriers of the carrier pairs, and the contact region attracts second type carriers of the carrier pairs;
• wherein a flow of the first type carriers and second type carriers of the carrier pairs is delayed and a start of the flow of the first type carriers and second type carriers of the carrier pairs is inversely proportional to an intensity of light incident on the light absorbing region.