Photo cell devices for phase-sensitive detection of light signals

A method comprising:

• providing a first vertical trench in a substrate;
• and
• providing a second vertical trench in the substrate laterally disposed from the first vertical trench, wherein a horizontal extent of the first and second vertical trenches extend in a first direction such that the first and second vertical trenches run in the first direction parallel to one another;
• providing a third vertical trench in the substrate;
• providing a fourth vertical trench in the substrate laterally disposed from the third vertical trench, wherein a horizontal extent of the third and fourth vertical trenches extend in a second direction generally perpendicular to the first direction, such that the third and fourth vertical trenches run in the second direction parallel to one another,
• wherein the first vertical trench, the second vertical trench, the third vertical trench and the fourth vertical trench collectively substantially enclose and thus define a square region of the substrate therebetween;
• alternately depleting a first region of the substrate surrounding the first vertical trench and a second region of the substrate surrounding the second vertical trench by alternately applying a voltage to a first vertical trench gate contact and a second vertical trench gate contact, and
• alternately depleting a third region of the substrate surrounding the third vertical trench and a fourth region of the substrate surrounding the fourth vertical trench by alternately applying a voltage to a third vertical trench gate contact and a fourth vertical trench gate contact,
• wherein the alternate depleting of the first, second, third and fourth regions comprising an interleaved biasing resulting in biasing of the various trenches serially in a circular fashion,
• wherein a lateral distance separating the first vertical trench and the second vertical trench is related to a doping level of the substrate such that upon operation a biasing of one of the first vertical trench, the second vertical trench, the third vertical trench and the fourth vertical trench results in formation of a fully depleted gap in a region centrally located between the first vertical trench, the second vertical trench, the third vertical trench, and the fourth vertical trench.