SBIR-STTR Award

Fabrication of stable, nearly 100% internal carrier collection efficiency silicon photodiodes (AXUV diodes) for 1 nm to 600 nm photons was successfully demonstrated by us several years ago. Owing to their excellent characteristics, these devices are being used by NIST as transfer standards in 5 nm to 250 nm range and aboard SOHO, SNOE and TIMED instruments for the EUV solar spectrum studies. Although, AXUV devices are being used in the present GOES EUV instrument, detectors for the 50 to 100 nm passband with stability and solar blindness required by GOES mission have not yet been demonstrated. Objective of this research is to realize AXUV diodes with Sn and In directly deposited filters for the 500 to 100 nm spectral region. In Phase I, fabrication of filtered diodes with five orders of magnitude visible light blocking will be demonstrated. In phase II, these devices with seven orders of magnitude visible light blocking and acceptable stability will be realized so that they will be useful with the transmission gratings to make the measurements desired by NOAA.

Potential Commercial Applications:
Owing to their light weight and long term stability the proposed AXUV filtered diodes will be extremely useful in future EUV solar space instrumentation. Other applications of the proposed devices are plasma diagnostics, process control during reactive film sputtering and XUV spectroscopy in general

IRD manufactures nearly 100% internal carrier collection efficiency silicon photodiodes which are being used presently aboard SOHO, SNOE, TIMED and SOURCE EUV instruments and will be used in GOES N, O and P spacecrafts to make the solar EVV measurements. Performance of these silicon photodiodes is not adequate for making the solar measurements in 50 nm to 100 nm (VUV) region because of the poor light blocking of the current Sn and In filters. Objective of this research is to realize silicon photodiodes with Sn and In directly deposited filters so that the diodes have less than 7 orders of magnitude response to visible light. Fabrication of VUV silicon carbide (SiC) photodiodes with directly deposited filters will also be investigated. Because of the wide band gap of SiC (3.2 eV), these devices are insensitive to visible light. Once successfully developed, these devices can be used in future GOES missions to make solar measurements in the problematic 50 nm to 100 nm passband.

Potential Commercial Applications:
Owing to their light weight and long term stability, the proposed AXUV filtered diodes will be extremely useful in future EUV solar space instrumentation. Other applications of the proposed devices are plasma diagnostics, process control during reactive film sputtering and EUV spectroscopy in general. The developed SiC detectors will be useful in almost all the applications where UV/EUV radiation is involved. Some of these applications are: EUV/ deep UV lithography, synchrotron radiation, air quality control, flame safeguard and fire detection, water purification, personal dosimetry, solar spectrum measurements and missile threat warning