Investigation of very high radiation hardness of 21 \(\varvec{\mu }\)m silicon self-biased detectors

The radiation damage of 21 \(\upmu \)m thick self-biased epitaxial \(\varDelta E\) detectors were tested as a function of fluence of 90 MeV \(^{14}\)N ions. Technology of production and technique of measurements of \(\varDelta E\) detectors were described. A new technique of soldering contact to thin detector is shown. In the present work the 21 \(\upmu \)m thick self-biased detectors marked as d4 and d5 show proper operation with the fluence about 4\(\cdot \)10\(^{15}\) \(\hbox {ions/cm}^{2}\) and the fluence about 8\(\cdot \)10\(^{15}\) \(\hbox {ions/cm}^{2}\), respectively. The charge collection efficiency of thin d5 \(\varDelta E\) detector was increased about double at fluence about 8\(\cdot \)10\(^{15}\) \(\hbox {ions/cm}^{2}\). The charge collection efficiency of thin d4 \(\varDelta E\) detector was increased about 35\(\%\) at fluence about 4\(\cdot \)10\(^{15}\) \(\hbox {ions/cm}^{2}\) followed decrease about 70\(\%\) of detector counting rate registration from fluence 9.1\(\cdot \)10\(^{15}\) \(\hbox {ions/cm}^{2}\) to fluence about 5\(\cdot \)10\(^{16}\) \(\hbox {ions/cm}^{2}\) due to partially removing of Al evaporated contact from detector surface as an effect of heavy ion irradiation. Increase of charge collection efficiency of thin self-biased detectors manufactured by the low-temperature technique was probably produced by increasing of build-in potential as an effect of activate carrier concentration of boron ions in epitaxial layer by heavy ion irradiation.