A device for perforating and fracturing a formation in a single trip includes shaped charges and a volume of a gas generator. When activated by detonation of the shaped charges, the gas generator forms a high-pressure gas, which includes steam, that expands to stress and fracture the formation. Suitable gas generating materials include hydrates and hydroxides. Other materials that can be employed with the gas generator include oxidizers and material such as metals that increase the available heat for the activation of the gas generator.