Measuring noise with an oscilloscope
A system with a single node: some R and some C, will have the total integrated noise defined EXACTLY by sqrt (K*T/C).

Thus a 10pF cap, at 290 degree K, produces exactly 20 microVolts RMS, regardlss of the value of the resistor.

Also, a 100pF cap would produce 1/sqrt(10) less noise, or about 6 microVolts RMS, regardless of the value of resistor.

To measure 6uV RMS in 10GHz bandwidth, the system noise density must be lower than 6uS/sqrt(10GHZ) = 6uV/sqrt(10^10) = 6uV/100,000 = 0.06 nanoVolts per rootHertz.

Given a 60 ohm resistor produces 1nanoVolt/rtHz noise density, and we need 0.06nV, or 16X smaller than 1nV, the total front end Rnoise my be 60/(16*16)  60/256 or 0.25 ohms.

Achieving Rnoise of 0.25 ohms will not happen.

Typical Rnoise (the rbb') of bipolars is 10 ohms or 100 ohms.

I cannot speak for typical rbb' for silicon-germanium bipolars.