Title :
Near-100% Quantum Efficiency of Delta Doped Large-Format UV-NIR Silicon Imagers
Author :
Blacksberg, Jordana ; Nikzad, Shouleh ; Hoenk, Michael E. ; Holland, Stephen E. ; Kolbe, William F.
Author_Institution :
NASA´´s Jet Propulsion Lab., California Inst. of Technol., Pasadena, CA
Abstract :
We have demonstrated a back surface process for back-illuminated high-purity p-channel charge-coupled devices (CCDs), enabling broadband coverage from the ultraviolet to near infrared (NIR). The process consists of the formation of a delta layer followed by a double layer antireflection (AR) coating. The process is performed below 450degC and is applied to fully fabricated CCDs with aluminum metallization. The delta doping process was demonstrated on 1 k times 1 k and 2 k times 4 k CCDs, which were found to exhibit low dark current and near reflection-limited quantum efficiency. Two broadband AR coatings were developed to cover the UV-visible and visible-NIR bands. These coatings consist of a double layer of SixNy and SiOx deposited by plasma enhanced chemical vapor deposition onto the back surface of a delta doped CCD. The thicknesses of the coating layers are adjusted for the desired bandpass.
Keywords :
CCD image sensors; antireflection coatings; elemental semiconductors; metallisation; semiconductor doping; silicon; Si; aluminum metallization; back surface process; charge-coupled devices; delta doping; double layer antireflection coating; large-format UV-NIR silicon imagers; low dark current; quantum efficiency; Charge coupled devices; Coatings; Dark current; Detectors; Doping; Electrodes; Laboratories; Optical arrays; Silicon; Surface treatment; Back illuminated; charge-coupled device (CCD); delta doping; fully depleted; high-purity silicon;
Journal_Title :
Electron Devices, IEEE Transactions on
DOI :
10.1109/TED.2008.2006779