It is known that the frequency behaviour of the silicon loss tangent shows a co-/ dependence,compared with the general tan (5Ã¢â‚¬â€ co behaviour for aluminum oxide and other oxides 1. For this reason,high purity, high resistivity silicon has been proposed to be used in dielectric windows for the high powerEC systems2. Loss tangent values as low as 10-3 and 10-4 have been measured at 15 and 145 GHzrespectively1,3. The main obstacle arises from its high sensitivity to ionizing radiation fields whichinduce large increases in the loss tangent due to radiation-induced electron-hole pairs1,4.
"Radiation induced reduction of silicon loss tangent", Proc. SPIE 2104, 18th International Conference on Infrared and Millimeter Waves, 21042O (30 August 1993); doi: 10.1117/12.2298528; https://doi.org/10.1117/12.2298528