The present invention relates to a growth inhibitor for forming a thin film, a method of forming a thin film using the growth inhibitor, and a semiconductor substrate fabricated by the method. More particularly, the growth inhibitor for forming a thin film according to the present invention is a compound represented by Chemical Formula 1: AnBmXoYiZj. A is carbon or silicon; B is hydrogen or an alkyl group having 1 to 3 carbon atoms; X is a leaving group having a bond dissociation energy of 50 to 350 KJ/mol; Y and Z independently include one or more selected from the group consisting of oxygen, nitrogen, sulfur, and fluorine and are different from each other; n is an integer from 1 to 15; o is an integer greater than or equal to 1; m is 0 to 2n+1; and i and j are integers from 0 to 3.