SnO 2 transistors show great promise as an alternative to existing In 2 O 3 -based transistors, considering their abundance and similar electronic properties. However, they suffer from highly negative onvoltages, large subthreshold swings, and high processing temperatures. One of the reasons for this is the residual chloride in the SnO 2 film, which negatively impacts the transistor by increasing the defects or acting as a dopant, thereby shifting the turn-on voltage negatively and increasing the subthreshold swing. Herein, we present a facile method of producing Si x Sn y O films with fewer chloride impurities, which can be used in highperformance, solution-processed TFTs. We employed AgNO 3 as an oxidizer for a low-temperature combustion reaction at 300 °C, which simultaneously acts as a chloride remover. We successfully reduced the turn-on voltage from −35.0 to −0.7 V using this route. The subthreshold swing was decreased from 2.91 to 0.32 V/dec using the same Sn concentration. The highest mobility obtained was 1.92 cm 2 /(V s) from the 0.25 M Sn precursor at a low drain voltage of 0.1 V. This method can be used as a general route for fabricating solution process-based SnO 2 TFTs and further expanding its application to flexible devices via low-temperature combustion.