Photolithography Patterning of Complementary Organic Circuits

Abstract

The application of organic electronics to display technologies, large area electronic paper (or plastics), organic light emitting diodes (OLEDs), organic solar cells, radio frequency identification tags, smart cards and chemical sensors has received a great deal of attention in recent years. The main advantages of using organic semiconductors (OSCs) are lowcost, low processing temperature, flexibility, light weight and rugged design. The substantial progress in this field has been driven not just by existing technologies, such as flat panel displays, but also by new applications, such as flexible solid-state lighting, lowcost printed integrated circuits, and plastic solar cells, to name a few. Performance-wise, organic thin-film transistors (OTFTs) are on par with their a-Si (amorphous silicon) counterparts. Since OTFT fabrication offers lower processing temperatures and lower cost, it has the potential to replace a-Si in the near future. To date, all organic complementary circuits have used stencil mask patterning. Stencil mask patterning is not practical for mass manufacturing; hence, a way to pattern organic complementary metal-oxide-semiconductor (O-CMOS) using photolithography is paramount. This is the goal of this thesis. In this dissertation the design and fabrication of improved OTFTs for electronic displays and complementary circuits are illustrated. Here, we demonstrated OTFTs that have excellent stability; hence, they are more suitable for the above-mentioned electronic applications. In addition, for the first time, successful photolithographic patterning of an n-channel organic semiconductor is demonstrated. These important results have enabled us to integrate the n-channel and p-channel organic materials using a complete photolithographic process in realizing O-CMOS.