Semiconductor integrated circuit with thick gate oxide word line driving circuit
View Patent ↗A semiconductor integrated circuit according to one aspect of the present invention may includes a plurality of driving circuits to drive a respective plurality of word lines with either a first voltage supplied from a first power supply or a second voltage supplied from a second power supply in accordance with a control signal, and a plurality of gate transistors in each of which a gate is connected to one of the plurality of word lines, and a connection state between a storage node and a bit line is changed based on the voltage provided to the word line connected to the gate. In the semiconductor integrated circuit, a gate oxide film of each of the plurality of gate transistors is thinner than a gate oxide film of each of transistors constituting the plurality of driving circuits.
1. A semiconductor device comprising a semiconductor substrate, a memory unit and a CPU which are both provided on the semiconductor substrate, the memory unit comprising:
a plurality of driving circuits, each of the driving circuits being provided to drive a respective plurality of word lines and to operate by using a first power supply voltage, and including a first transistor, the first transistor having a first gate electrode and a first gate oxide film;
a plurality of memory cells, each of the memory cells having a second transistor connected to an associated one of the word lines, the second transistor having a second gate electrode and a second gate oxide film; and
a control circuit being provided to control writing data to at least one of the memory cells and reading data from at least one of the memory cells and to operate by using a second power supply voltage which is lower than the first power supply voltage, the control circuit including a third transistor having a third gate electrode and a third gate oxide film,
wherein the first gate oxide film has a first thickness which is thicker than that of the second gate oxide film,
wherein the second gate oxide film has a second thickness which is thicker than that of the third gate oxide film.
2. The semiconductor device according to claim 1 , wherein the control circuit comprises a sense amplifier.
3. The semiconductor device according to claim 1 , wherein the CPU is operated by using the second power supply voltage and includes a fourth transistor having a fourth gate electrode and a fourth gate oxide film which has a fourth thickness thinner than the second thickness.
4. The semiconductor device according to claim 1 further comprises a boosting circuit provided on the semiconductor substrates, the boosting circuit generating the first power supply voltage by boosting an external voltage.
5. The semiconductor device according to claim 4 , further comprises a step-down voltage circuit provided on the semiconductor substrate, the step-down voltage circuit generating the second power supply voltage by reducing the external voltage.
6. A semiconductor device comprising a semiconductor substrate, a memory unit and a CPU which are both provided on the semiconductor substrate, the memory unit comprising:
a plurality of driving circuits, each of the driving circuits being provided to drive a respective plurality of word lines and to operate by using a first voltage, and including a first transistor, the first transistor having a first gate electrode and a first gate oxide film;
a plurality of memory cells, each of the memory cells having a second transistor connected to an associated one of the word lines, the second transistor having a second gate electrode and a second gate oxide film; and
a control circuit being provided to control writing data to at least one of the memory cells and reading data from at least one of the memory cells, the control circuit including a third transistor having a third gate electrode and a third gate oxide film,
wherein the first gate oxide film has a first thickness which is thicker than that of the second gate oxide film,
wherein the second gate oxide film has a second thickness which is thicker that of the third gate oxide film,
wherein the first voltage is applied to the second gate electrode to activate the second transistor,
wherein a second voltage is applied to the third gate electrode to activate the third transistor,
wherein the first voltage is higher than the second voltage.
7. A semiconductor device on the semiconductor substrate, comprising:
a memory unit; and
a CPU coupled to the memory unit,
wherein the memory unit comprises:
a plurality of word lines;
a plurality of word line driving circuits each including:
a first transistor having:
a first gate electrode,
a first gate oxide film and
whose a source-drain path thereof coupled between a first power supply voltage line and the corresponding one word line;
a plurality of memory cells each including:
a second transistor having
a second gate electrode coupled to the corresponding one word line and
a second oxide film whose thickness thereof is thinner than that of the first gate oxide film; and
a control circuit configured to control writing data to one or more of the plurality of memory cells and/or reading data from one or more of the plurality of memory cells and to operate by using a second power supply voltage lower than the first power supply voltage, the control circuit including:
a third transistor having a third gate electrode and
a third gate oxide film whose thickness thereof is thinner than that of the second gate oxide film.