56.4: Formation of Single‐Layer Al‐Alloy Interconnection for Source and Drain of a‐Si TFT Using One‐Wet‐One‐Dry Etching with Four‐Mask Process

Abstract

AbstractSingle layer Al‐alloy interconnection for source and drain of amorphous Si (a‐Si) thin film transistor (TFT) is demonstrated by direct‐contact technology with no barrier metals at the interfaces with both ITO and a‐Si. Thermally stable contacts were formed on a‐Si with a buried nitridation layer while maintaining the contact resistivity as low as 0.1Ωcm2. Excessive interdiffusion between the Al‐alloy electrode and a‐Si that can degrade TFT characteristics was suppressed by the nitridation layer. The Al‐alloy direct contact technology, combined with one‐wet‐one‐dry etching with four‐mask process, drastically simplifies the the TFT fabrication process and contributes to cost reduction of a‐Si TFT LCD.