Fabrication method of polycrystalline silicon liquid crystal display device

A method for fabricating a transreflective liquid crystal display device, comprising:

• forming an active layer on a substrate;
• forming a first insulation layer including a silicon oxide layer on the active layer;
• forming a gate electrode on the first insulation layer;
• forming a second insulation layer including a porous silicon nitride layer on the gate electrode, the silicon nitride layer formed by deposition using a plasma including N2 gas of about 1700 to 2300 sccm, NH3 gas of about 600 to 800 sccm and SiH4 gas of about 130 to 150 sccm under conditions of a voltage of about 1500 to 1700 V and pressure of about 1400 to 1600 mTorr;
• forming a transparent electrode layer including Indium Tin Oxide (ITO) on the second insulation layer;
• wet-etching the transparent electrode, the second insulation layer and the first insulation layer to form holes exposing the active layer;
• forming a pixel electrode by patterning the transparent electrode;
• forming a source electrode connected to the active layer through one of the holes and a drain electrode connected to the active layer and the pixel electrode through one of the holes;
• forming a passivation layer on the source and drain electrodes, and the second insulation layer;
• etching the passivation layer to form a hole exposing the drain electrode;
• and
• forming a reflective electrode connected to the drain electrode.