US5438537A
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Static random access memory which has a pair of thin film transistors and wherein the capacitance and resistance between the gate electrodes and the conductor layers are increased so as to reduce the time constant between them
Abstract A static random access memory of the thin film transistor load type which is enhanced in soft error resistance without involving an increase of the area of a cell is disclosed. A conductor layer is connected to the gate electrode of a first one of a pair of thin film transistors which serve as load means of each cell and is formed as a different layer from the first thin film transistor. The conductor layer is layered on a conductor layer of the other second thin film transistor with an insulating layer interposed therebetween to form a coupling capacity between the conductor layer connected to the gate electrode of the first thin film transistor and the conductor layer of the second thin film transistor. Resistors are interposed between the gates and active layers of the first and second thin film transistors and storage nodes connected to the first and second thin film transistors.
A static random access memory of the thin film transistor load type comprising, first and second thin film load transistors, a pair of driver transistors, and a pair of word transistors, a first polycrystalline layer which forms the gate of said first thin film load transistor, a second polycrystalline layer which forms the gate of said second thin film load transistor, a third polycrystalline layer spaced from first and second polycrystalline layers and capacitively coupling them together and forming a coupling capacitance therebetween, fourth and fifth polycrystalline layers which, respectively, form the gates of said pair of driver transistors, a first resistor formed in a through-hole between said first and said fourth polycrystalline layer so as to resistively couple them together, and a second resistor formed in a through-hole between said second and fifth polycrystalline layer so as to resistively couple them together, and wherein the product of the coupling capacitance and the resistance of said first resistor defines a time constant which determines the response speed of said random access memory.
Claim 2
Dependent Claim
172 words
A static random access memory of the thin film transistor load type comprising, first and second thin film load transistors, a pair of driver transistors, and a pair of word transistors, a first polycrystalline layer which forms the gate of said first thin film load transistor, a second polycrystalline layer which forms the gate of said second thin film load transistor, a third polycrystalline layer spaced from first and second polycrystalline layers and capacitively coupling them together and forming a coupling capacitance therebetween, fourth and fifth polycrystalline layers which, respectively, form the gates of said pair of driver transistors, a first resistor formed in a through-hole between said first and said fourth polycrystalline layer so as to resistively couple them together, and a second resistor formed in a through-hole between said second and fifth polycrystalline layer so as to resistively couple them together, and wherein the product of the coupling capacitance and the resistance of said first resistor defines a time constant which determines the response speed of said random access memory.