Manufacture of electronic devices comprising thin-film transistors using

Abstract

In the manufacture of a liquid-crystal display or other large area electronic device, thin-film transistors are formed on a substrate (10) from a thin film (1) of disordered semiconductor material which accommodates the transistor channel regions and has a high density of trapping states. A masking pattern (13) masks areas of the semiconductor film (1) where the thin-film transistors are to be formed. The unmasked areas of the film (1) are etched away to leave the semiconductor film bodies for the transistors. The resulting transistors are found to have an undesirable leakage current through the channel region, even after adopting several prior art measures to reduce the high leakage. By implanting a dopant stripe (5) along their edges, the present invention reduces leakage currents along the edges of the channel region in the etched disordered semiconductor material (1). The implantation of ions (15) is effected through bevelled edge portions (13) of the masking pattern (13) so as to form the dopant stripe (5) across the thickness of the semiconductor film material (10). The thickness of the masking pattern (13) is sufficient to mask against implantation of the ions (15) except below the bevelled edge portions (14). The technology is compatible with the use of a substrate (10) not able to withstand temperatures of more than about 700.degree. C.