What's the loss tangent value of high sensitivity silicon?

I am trying to simulate a CPW on a high-resistivity silicon (5000 ohm.cm) substrate. I am wondering what will be the correct value for loss tangent of this substrate. Can anyone tell me if there is any reference to look for?

hello, I have found the following data on silicon substrate (from the book of Leif Halbo and Per Ohlckers: electronic components, packaging and production):

1. SiC:
resistance (ohm*cm) = 10^13
eps = 15 to 45
tand = 5*10^-2

2. Si
resistance (ohm*cm) = 10^4 (they also indicate 10^-4, I dont understand this well)
eps = 11.9
tand = 4*10^-2 / 4*10^-3

3. SiO2
resistance (ohm*cm) = 10^6
eps = 3.9
tand = 3*10^-2

4. Si3N4
resistance (ohm*cm) = 10^12
eps = 7.5
tand = ---

If I were you, I would ask the substrate manufacturer, to be 100 % sure. Do you have a data sheet (substrate material specification)?

Hello again, I found new data in the same book.

Indicates "high resistive silicon" rho = 10^3 ohm*cm

epsilon = 11.9
tand = 0.015

hope it helps. regards