Floating gate memory cells in vertical memory. A control gate is formed between a first tier of dielectric material and a second tier of dielectric material. A floating gate is formed between the first tier of dielectric material and the second tier of dielectric material, wherein the floating gate includes a protrusion extending towards the control gate. A charge blocking structure is formed between the floating gate and the control gate, wherein at least a portion of the charge blocking structure wraps around the protrusion.

An object of one embodiment of the present invention is to provide a semiconductor device with a novel structure in which stored data can be stored even when power is not supplied in a data storing time and there is no limitation on the number of times of writing. The semiconductor device includes a first transistor which includes a first channel formation region using a semiconductor material other than an oxide semiconductor, a second transistor which includes a second channel formation region using an oxide semiconductor material, and a capacitor. One of a second source electrode and a second drain electrode of the second transistor is electrically connected to one electrode of the capacitor.

To provide a memory element where a desired potential can be stored as data without an increase in the number of power source potentials. The memory element stores data in a node which is brought into a floating state by turning off a transistor a channel of which is formed in an oxide semiconductor layer. The potential of a gate of the transistor can be increased by capacitive coupling between the gate and a source of the transistor. With the structure, a desired potential can be stored as data without an increase in the number of power source potentials.

A semiconductor device that suppresses operation delay due to stop and restart of the supply of a power supply potential is provided. A potential corresponding to data held while power supply potential is continuously supplied is backed up in a node connected to a capacitor while the supply of the power supply potential is stopped. Then, by utilizing change in resistance of a channel in a transistor whose gate is the node, the data is restored with restart of the supply of the power supply potential. Note that by supplying a high potential to the node before the data back up, high-speed and accurate data back up is possible.

A first transistor including a channel formation region, a first gate insulating layer, a first gate electrode, and a first source electrode and a first drain electrode; a second transistor including an oxide semiconductor layer, a second source electrode and a second drain electrode, a second gate insulating layer, and a second gate electrode; and a capacitor including one of the second source electrode and the second drain electrode, the second gate insulating layer, and an electrode provided to overlap with one of the second source electrode and the second drain electrode over the second gate insulating layer are provided. The first gate electrode and one of the second source electrode and the second drain electrode are electrically connected to each other.

To provide a semiconductor device having a substrate contact in a deep trench thereof and having an improved characteristic. A PVD-metal film (metal film formed by PVD) is used as a first barrier metal film which is a lowermost layer barrier metal film formed in a deep trench penetrating an n type epitaxial layer and a reaching a layer therebelow. Such a configuration makes it possible to stably form a metal silicide layer at a boundary between the PVD-metal film and a silicon layer therebelow (or silicon substrate) and thereby stabilize the contact resistance.

The degree of integration of a semiconductor device is enhanced and the storage capacity per unit area is increased. The semiconductor device includes a first transistor provided in a semiconductor substrate and a second transistor provided over the first transistor. In addition, an upper portion of a semiconductor layer of the second transistor is in contact with a wiring, and a lower portion thereof is in contact with a gate electrode of the first transistor. With such a structure, the wiring and the gate electrode of the first transistor can serve as a source electrode and a drain electrode of the second transistor, respectively. Accordingly, the area occupied by the semiconductor device can be reduced.

Provided is a highly integrated semiconductor device, a semiconductor device with large storage capacity with respect to an area occupied by a capacitor, a semiconductor device capable of high-speed writing, a semiconductor device capable of high-speed reading, a semiconductor device with low power consumption, or a highly reliable semiconductor device. The semiconductor device includes a first transistor, a second transistor, and a capacitor. A conductor penetrates and connects the first transistor, the capacitor, and the second transistor. An insulator is provided on a side surface of the conductor that penetrates the capacitor.

A semiconductor device includes: a source line; a bit line; a word line; a memory cell connected to the bit line and the word line; a driver circuit which drives a plurality of second signal lines and a plurality of word lines so as to select the memory cell specified by an address signal; a potential generating circuit which generates a writing potential and a plurality of reading potentials to supply to a writing circuit and a reading circuit; and a control circuit which selects one of a plurality of voltages for correction on a basis of results of the reading circuit comparing a potential of the bit line with the plurality of reading potentials.

A highly integrated semiconductor device that holds data and includes a first semiconductor layer, a first gate insulating film over the first semiconductor layer, a first gate electrode over the first gate insulating film, a second semiconductor layer over the first gate electrode, a conductive layer over the second semiconductor layer, a second gate insulating film covering the second semiconductor layer and the conductive layer, and a second gate electrode covering at least part of a side surface of the second semiconductor layer with the second gate insulating film interposed therebetween. An end portion of the second semiconductor layer is substantially aligned with an end portion of the conductive layer.