Method of controlling a capacitance of a thin film transistor liquid crystal display (TFT-LCD) storage capacitor

A method of controlling a capacitance of a TFT-LCD storage capacitor, comprising:

• forming a gate and a bottom electrode on a transparent substrate;
• sequentially forming a dielectric layer and a silicon nitride layer on the transparent substrate;
• forming an undoped amorphous silicon layer on the silicon nitride layer;
• forming an etching mask on the undoped amorphous silicon layer;
• forming two doped amorphous silicon layers on a portion of the undoped amorphous silicon layer and the etching mask, the two doped amorphous silicon layers being spaced apart and located on either side of the gate, wherein an etching selectivity ratio of the undpoed and doped amorphous silicon layers over the dielectric layer being not less than about 5.0;
• forming a source and a drain respectively on the two doped amorphous silicon layers, the undoped amorphous silicon layer serving as a channel between the source and the drain;
• forming a passivation layer over the transparent substrate, the passivation layer comprising a contact window to expose the source or the drain;
• and
• forming a pixel electrode on the passivation layer, the pixel electrode connecting the exposed source or drain electrically through the contact window, and an overlap between the pixel electrode and the bottom electrode forming a storage capacitor.