Integrated Avalanche Photodiode arrays
View Patent ↗The present disclosure includes devices for detecting photons, including avalanche photon detectors, arrays of such detectors, and circuits including such arrays. In some aspects, the detectors and arrays include a virtual beveled edge mesa structure surrounded by resistive material damaged by ion implantation and having side wall profiles that taper inwardly towards the top of the mesa structures, or towards the direction from which the ion implantation occurred. Other aspects are directed to masking and multiple implantation and/or annealing steps. Furthermore, methods for fabricating and using such devices, circuits and arrays are disclosed.
1. A photo detector array, comprising:
a substrate layer;
a plurality of doped semiconductor layers including a first semiconductor layer doped with a first dopant disposed above said substrate and a second semiconductor layer doped with a second dopant disposed above said first semiconductor layer and proximal thereto;
said first and second semiconductor layers being ion implanted in a plurality of selected regions thereof at generally positive lateral profile angles with respect to a normal to said first and second semiconductor layers so as to form a corresponding plurality of mesa structures having angled side profiles in said first and second semiconductor layers; and
a photon detection circuit including a plurality of ohmic connections to one or more of said mesa structures so as to provide at least one output signal of said array corresponding to one or more detected photon interactions within said mesa structures.
2. The array of claim 1 , said photon detection circuit comprising a passive quench circuit.
3. The array of claim 1 , each of said mesa structures separated from the others in said array by an ion implanted isolation region.
4. The array of claim 1 , said plurality of virtual mesa structures having a common surrounding electrically isolating region formed around the same by one or more ion implantation processes.
5. The array of claim 4 , said common surrounding electrically isolating region having a first thickness, resulting from a first ion implantation process, and a second thickness of said plurality of selected ion implanted regions, resulting from a second ion implantation process, that define said virtual mesa structures.
6. The array of claim 5 , said second ion implantation density being greater than said first ion implantation density.
7. The array of claim 1 , at least a portion of one of said first and second semiconductor layers having a graded density doping profile as a function of its thickness.