Methods and devices for charge management for three-dimensional sensing

For use in a system that illuminates a target with optical energy having a modified periodic waveform that includes a high frequency component and that detects with at least one semiconductor photodetector a fraction of said optical energy reflected by said target, a method of improving detection performance comprising the following steps:

• providing each said semiconductor photodetector with a first group and a second group of spaced-apart elongated structures formed on a substrate, wherein a distance in an x-direction separating adjacent said structures is substantially less than a length in a y-direction of said structures;
• dynamically biasing said semiconductor photodetector such that detection-generated charge within said substrate is moved at a first rate in said x-direction for local collection by at least at a first region of said elongated structures, and at least some of said detection-generated charge at said first region is moved at a second rate in said y-direction for collection at a second region of said elongated structures;
• wherein performance of said semiconductor photodetector is substantially dependent on said first rate and is substantially independent of said second rate.

For use in a system that illuminates a target with optical energy having a modulated periodic waveform that includes a high frequency component and that detects a fraction of said optical energy reflected by said target, at least one CMOS-implementable semiconductor photodetector used with said system to detect said fraction, said semiconductor photodetector including:

• a first group and a second group of spaced-apart elongated structures formed on a substrate, wherein distance in an x-direction separating adjacent said structures is substantially less than a length in a y-direction of said structures;
• said semiconductor photodetector being biasable such that detection-generated charge within said substrate is moved at a first rate in said for local collection by at least at a first region of said elongated structures, and at least some of said detection-generated charge at said first region is moved at second rate in said y-direction for collection at a second region of said elongated structures;
• wherein performance of said semiconductor photodetector is substantially dependent on said first rate and is substantially independent of said second rate.