The first thin-film transistor 210 may include a first semiconductor layer 211 including, for example, amorphous silicon, polysilicon, or an organic semiconductor material, a first gate electrode 213, a first source electrode 215a, and a first drain electrode 215b. To ensure insulation between the first semiconductor layer 211 and the first gate electrode 213, a first gate insulating layer 121 including an inorganic material such as, for example, silicon oxide, silicon nitride, and/or silicon oxynitride may be interposed between the first semiconductor layer 211 and the first gate electrode 213. In addition, an interlayer insulating layer 131 including an inorganic material such as, for example, silicon oxide, silicon nitride, and/or silicon oxynitride may be arranged on the first gate electrode 213, and the first source electrode 215a and the first drain electrode 215b may be arranged on the interlayer insulating layer 131. The first gate insulating layer 121 and the interlayer insulating layer 131 including the inorganic material may be formed by using, for example, a chemical vapor deposition (CVD) process or an atomic layer deposition (ALD) process. The same is applied to exemplary embodiments to be described below.