Scalability of silicon-based phase-change oscillators is investigated through experimental and computational studies. These relaxation oscillators are composed of a small volume of silicon, dc biased through a load resistor and a capacitor, which melts due to self-heating and resolidifies upon discharge of the load capacitor. These phase changes lead to high-amplitude current spikes with oscillation frequency that scales with supply voltage, RC time constant, power delivery condition, and heating and cooling rates of the wire. Experimental results are obtained from structures fabricated using silicon-on-insulator substrates. Scaling effects of various parameters are explored using 3-D finite-element simulations coupled with SPICE models.