Thin film transistor, its manufacture method and display device

A thin film transistor comprising:

• an insulating substrate;
• a first insulating buffer layer formed on a surface of said insulating substrate;
• a light shielding layer formed on a surface of said first insulating buffer layer;
• a second insulating buffer layer formed on a surface of said light shielding layer;
• a first silicon layer formed on a surface of said second insulating buffer layer;
• a gate insulating film formed on a surface of said first silicon layer;
• a gate electrode formed on a surface of said gate insulating film;
• and
• source/drain electrodes electrically connected to said first silicon layer on both sides of said gate electrode,
• wherein said light shielding layer is made of silicon or is made of an upper layer and a lower layer, said lower layer being a metal layer of refractory metal selected from a group consisting of molybdenum, titanium, neodymium, tungsten and tantalum or alloy containing said selected refractory metal or metals, or a silicide layer of said selected refractory metal or metals, and said upper layer being a silicon layer formed on said lower layer.

A display device having pixel drive transistors and peripheral circuit transistors for controlling operations of said pixel drive transistors, wherein:

• said peripheral circuit transistor comprises an insulating substrate,
• a first insulating buffer layer formed on a surface of said insulating substrate, a first silicon layer formed on a surface of said first insulating buffer layer;
• a second insulating buffer layer formed on a surface of said first silicon layer and a second silicon layer formed on a surface of said second insulating buffer layer, said second silicon layer being an active layer of said peripheral circuit transistor;
• and
• said pixel drive transistor comprises a third silicon layer formed on the surface of said first insulating buffer layer, said third silicon layer being a same layer as said first silicon layer and an active layer of said pixel drive transistor.