Polymorphous Silicon: A Promising Material for Thin-Film Transistors for Low-Cost and High-Performance Active-Matrix OLED Displays

Hydrogenated polymorphous Silicon allows to fabricate TFTs with very interesting characteristics including better threshold voltage stability than a-Si TFTs, lower leakage current than µc-Si: H TFTs and excellent uniformity. Investigation of threshold voltage shift mechanisms of pm-Si: H TFTs has shown a specific semiconductor material degradation with different activation energies compared to a-Si: H TFTs. TEM analysis has evidenced for the first time a significant structural difference between pm-Si: H and a-Si: H materials, in the TFT device configuration. Pm-Si: H appears to be very suitable for low cost and high performance AM-OLED fabrication.