Patent ID: 7948170
Filing Date: 2011-05-24
Classification: H01L

Abstract:
1. A pixel having a vertical architecture in which a thin film transistor (TFT)-based backplane and an organic light emitting device (OLED) are formed on the same substrate, said pixel comprising: a substrate having a substantially flat upper surface; a TFT-based backplane formed on said substantially flat upper surface of said substrate for electrically driving the OLED, said TFT-based backplane having a vertical profile facing away from said upper surface of said substrate; a planarization dielectric layer formed on top of said TFT based backplane and having a smooth, planarized upper surface for planarizing said vertical profile on the TFT based backplane; the OLED formed on top of said planarized surface of said planarization dielectric layer, said OLED device having a bottom electrode, a top electrode, and the organic light emitting layer between the bottom and top electrodes, said bottom electrode being formed on said planarized surface, said top electrode being transparent so that light to be emitted by said OLED travels in a direction opposite to said substrate to form a top-emitting OLED; the OLED being vertically integrated with the TFT based backplane via the planarization dielectric layer, the portion of the organic light emitting layer between the bottom and top electrodes of the OLED at least partially overlapping a gate, source, or drain node of a transistor of the TFT based backplane; a first via in the planarization dielectric layer, for providing a communication path between the TFT based backplane and the OLED, wherein a sidewall of the first via is sloped against the TFT based backplane; and an additional dielectric layer deposited on top of said bottom electrode for covering at least one of said first via and edges of said bottom electrode while leaving the rest of said bottom electrode uncovered, said organic light emitting layer being applied over said dielectric cap.