A bulk knife-edged as-deposition self-patterning structure for Greek-cross and organic thin film transistors

A silicon bulk-micromachined knife-edged structure was developed and applied to Greek cross and pentacene thin film transistor (TFT) for new material characterization. By the entrant knife-edge, a target material layer is self-patterned as deposited, thus enabling heat-cycle and chemical compatibility test without inducing degradation of materials due to lithography. In knife-edged Greek cross application, underlying bulk Si layer works as a large heat sink. As a result, joule heat causing resistance variation has been substantially suppressed. Together with IV-extrapolation method, resistance curve is linearized, yielding representative value with <1% of least-squares error. Knife-edge is also applicable to pattern sensitive materials such as pentacene. Pentacene was deposited on knife-edged TFT test-bed and I_d-V_d characteristics were measured.