Very Fast Subarray Position Calculation for Minimizing Sidelobes in Sparse Linear Phased Arrays

An insulated-gate thin film transistor is provided with low leakage drain current. A second semiconductor layer makes contact with the source electrode and the semiconductor layer forming the channel of the transistor at least between the source and drain electrodes. The second semiconductor layer is of opposite type conductivity from the channel semiconductor layer and preferably forms a PN heterojunction with the channel semiconductor layer. Alternatively, a metal layer may be used in place of the second semiconductor to form a Schottky-barrier junction with the channel semiconductor layer instead of a PN junction. Preferably, the channel semiconductor layer and the second semiconductor layer or the metal layer are sequentially evaporation deposited through the same deposition mask onto a substrate from evaporant sources spaced substantially different distances from the substrate so that the sequential layers are deposited on first and second overlapping areas of the substrate.