We measure the electrical noise characteristics of doped silicon microcantilevers during cantilever self-heating over the temperature range 296-781 K. The dominant noise source is 1/f below about 10 kHz, while at higher frequency, the dominant noise source is Johnson noise. The 1/f noise matches the Hooge model. The noise floor is about 10 nV/Hz1/2 and depends upon temperature, matching the theoretical Johnson noise. The Johnson noise-limited temperature resolution is about 1 μK/Hz1/2. [ABSTRACT FROM AUTHOR]