Array with metal scan lines controlling semiconductor gate lines

DETAILED DESCRIPTION The invention addresses problems that affect arrays of circuitry formed on substrates.
A two-dimensional (2D) array, for example, can include two sets of conductive lines extending in perpendicular directions, as illustrated by FIG.
3 of the Wu article described above.
Each line extending in one direction can provide signals to a column of the array; each line extending in another direction can provide signals to a row of the array.
Conventionally, each row-column position in a 2D array includes circuitry, sometimes called a "cell," that responds to or provides signals on the lines for the cell's row and column combination.
Through one set of parallel lines, illustratively called "data lines," each cell receives or provides signals that determine or indicate its state.
Through the other set of parallel lines, illustratively called "scan lines," each cell along a scan line receives a signal that enables the cell to receive signals from or to provide signals to its data line.
The area of each cell that is bounded by data lines and scan lines, referred to herein as the "cell area," can serve as a transducer, providing or receiving signals to or from sources outside the array.
In conventional arrays, each scan line provides a periodic scan signal that enables a component in each cell connected to the scan line to receive a signal from or provide a signal to its data line during a brief time interval of each cycle.
Therefore, tight synchronization of the scan signals with signals on the data lines is critical to successful array operation.
Also, the scan signals must maintain high quality transitions across an array.
If a scan line has high resistance, its propagation delay is long, which causes signal distortion, preventing accurate signal synchronization and causing inaccurate loading or extraction of data.
Some conventional techniques address the scan line resistance problem by using metal scan lines.
But each cell's circuitry conventionally includes a semiconductor channel, and the conductivity of the channel is conventionally controlled by the scan signals, also referred to as "gate signals" by analogy to the gate of a transistor