Thermal Noise in Double Injection

Noise measurements from 500 kHz to 22 MHz and at ambient temperatures $T$ between 140 and 350°K have been performed on a double-injection silicon diode as a function of operating point. The results indicate that at high frequencies, (i) the noise increases linearly with $T$, and (ii) the noise also depends linearly on the differential conductance $g$ at the same frequency. Within at most a 5% error, the high-frequency noise is quantitatively represented by Nyquist's formula $〈i^2〉=4\mathrm{kTg}\Delta f$ throughout the experimental range. This proves the thermal nature of the high-frequency noise of double injection. Possible limits on this result and its comparison with alternative theories are discussed.