A Two-Dimensional Avalanche Photodiode Array Suitable for Near IR LADAR

SMD proposes the design and fabrication of a two-dimensional APD array. A novel APD array is proposed which requires low bias voltages, thus making it compatible with both CMOS and CCD multiplexer designs. The on-chip CMOS/CCD circuitry will allow for multiplexing of a large number of pixels to a single output. Further, each pixel in the APD array will have its own range detection circuitry allowing for time-of-flight measurements on a pixel by pixel basis for potentially very large arrays. Quantum efficiency of the APD array will be enhanced in the infrared range through the deposition of a unique coating on the surface of the silicon. When the coating is exposed to infrared radiation, a visible orange secondary emission is observed. Thus, the coating converts infrared energy into a wavelength more compatible with silicon APD detection. The combination of the novel low voltage APD design with the wavelength converting coating will result in a new generation of high performance APD arrays. Under Phase I, SMD proposes to experimentally demonstrate key components of the proposed concept Phase II will result in a fieldable 25x25 APD array with on-chip range detection circuitry and enhanced IR sensitivity.