Dual-independent-gate silicon FinFET has demonstrated a steep subthreshold slope (SS) when a positive feedback induced by weak impact ionization is triggered. In this paper, we study the temperature dependency of the steep SS by characterizing the fabricated device from 100 to 380 K. The measured characteristics of SS show a reduced sensitivity to temperature as compared to conventional MOSFETs. Based on the temperature-dependent characterization, we further analyze the steep-SS characteristics and propose feasible improvements for optimizing the device performance.