An object is to provide a semiconductor device of which a manufacturing process is not complicated and by which cost can be suppressed, by forming a thin film transistor using an oxide semiconductor film typified by zinc oxide, and a manufacturing method thereof. For the semiconductor device, a gate electrode is formed over a substrate; a gate insulating film is formed covering the gate electrode; an oxide semiconductor film is formed over the gate insulating film; and a first conductive film and a second conductive film are formed over the oxide semiconductor film. The oxide semiconductor film has at least a crystallized region in a channel region.

Semiconductor device, and manufacturing method thereof

An electrically erasable programmable read only memory (EEPROM) having a non conducting charge trapping dielectric, such as silicon nitride, sandwiched between two silicon dioxide layers acting as electrical insulators is disclosed. The invention includes a method of programming, reading and erasing the EEPROM device. The non conducting dielectric layer functions as an electrical charge trapping medium. A conducting gate layer is placed over the upper silicon dioxide layer. The memory device is programmed in the conventional manner, using hot electron programming, by applying programming voltages to the gate and the drain while the source is grounded. Hot electrons are accelerated sufficiently to be injected into the region of the trapping dielectric layer near the drain. The device, however, is read in the opposite direction from which it was written, meaning voltages are applied to the gate and the source while the drain is grounded. Application of relatively low gate voltages combined with reading in the reverse direction greatly reduces the potential across the trapped charge region. This permits much shorter programming times by amplifying the effect of the charge trapped in the localized trapping region. In addition, the memory cell can be erased by applying suitable erase voltages to the gate and the drain so as to cause electrons to be removed from the charge trapping region of the nitride layer. Similar to programming, a narrower charge trapping region enables much faster erase cycles.

Two bit non-volatile electrically erasable and programmable semiconductor memory cell utilizing asymmetrical charge trapping

Structures, methods of manufacturing and methods of use of electrically programmable read only memories (EPROM) and flash electrically erasable and programmable read only memories (EEPROM) include split channel and other cell configurations. An arrangement of elements and cooperative processes of manufacture provide self-alignment of the elements. An intelligent programming technique allows each memory cell to store more than the usual one bit of information. An intelligent erase algorithm prolongs the useful life of the memory cells. Use of these various features provides a memory having a very high storage density and a long life, making it particularly useful as a solid state memory in place of magnetic disk storage devices in computer systems.

Highly compact EPROM and flash EEPROM devices

A memory cell array has a first and a second storage area. The first storage area has a memory elements selected by an address signal. The second storage area has a memory elements selected by a control signal. A control circuit has a fuse element. When the fuse element has been blown, the control circuit inhibits at least one of writing and erasing from being done on the second storage area.

Nonvolatile Semiconductor Memory Device

Semiconductor chips are used today not only to control systems, but also to protect them against security threats. A continuous battle is waged between manufacturers who invent new security solutions, learning their lessons from previous mistakes, and the hacker community, constantly trying to break implemented protections. Some chip manufacturers do not pay enough attention to the proper design and testing of protection mechanisms. Even where they claim their products are highly secure, they do not guarantee this and do not take any responsibility if a device is compromised. In this situation, it is crucial for the design engineer to have a convenient and reliable method of testing secure chips.

Semi-invasive attacks – A new approach to hardware security analysis

A semiconductor integrated circuit device is provided on a semiconductor substrate, and includes a plurality of word lines, a plurality of data lines, and a plurality of electrically programmable and erasable non-volatile memory cells respectively coupled to the plurality of word lines and to the plurality of data lines. The erasable non-volatile memory cell each includes a MIS transistor having a floating gate having a first level polycrystalline silicon layer, a source, and a drain coupled to the corresponding data line, and a control gate formed of a semiconductor region in the semiconductor substrate, the control gate being coupled to the corresponding word line.

Semiconductor integrated circuit and nonvolatile memory element

A semiconductor integrated circuit device is provided which includes first field effect transistors of an LDD structure having a floating gate as memory cells and second field effect transistors of the LDD structure as elements other than the memory cells. A shallow, low impurity concentration region of the first field effect transistor which is a part of its source or drain region has a higher impurity concentration than a shallow, low impurity concentration region of the second field effect transistor which is a part of its source or drain region. The device is particularly useful in an EPROM arrangement.

Semiconductor device of an LDD structure having a floating gate

A flash-erase EEPROM cell which consists of a single floating gate transistor is described. The cell is based on self-aligned double polysilicon stacked gate structure without a select transistor. It is programmed and erased by hot electrons at the drain edge similar to a UV-EPROM, and by Fowler-Nordheim tunneling of electrons from the floating gate to the source, respectively. An asymmetry in source and drain regions is introduced to enable fast program/erase operation. In addition, an n+concentration in the source region is optimized to achieve reproducible erasure, which is indispensable to avoid over-erasing problem. The optimized cell enables an erasing time of less than one millisecond with 12. 5 V on the source, and a scatter of erased Vth is almost negligible. Endurance and data retention characteristics is also adequate for implementation in memory chips. The small cell area of 9.3µm2is accomplished in a 0.8µm technology.

A flash-erase EEPROM cell with an asymmetric source and drain structure

Disclosed is a semiconductor integrated circuit device which includes first field effect transistors of an LDD structure having a floating gate as memory cells and second field effect transistors of the LDD structure as elements other than the memory cells, and which is used as EPROM. A shallow, low impurity concentration region of the first field effect transistor as a part of its source or drain region has a higher impurity concentration than a shallow, low impurity concentration region of the second field effect transistor as a part of its source or drain region.

Method of making semiconductor device with memory cells and peripheral transistors

The invention relates to a tunnel erasing device for a non-volatile semiconductor memory device comprising a source region and a drain region, a floating gate electrode having a part superposed on at least one of them through a gate insulating layer, and a control gate electrode disposed over the floating gate electrode through an interlayer insulating layer and is characterized as having a preliminary erasing operation in which a voltage is so applied to at least one of the source or drain region, with the control gate electrode grounded, that a relatively lower voltage than a predetermined voltage is applied preliminarily prior to applying thereto the predetermined voltage.

Kazuhiro Komori

Papers

Semiconductor integrated circuit and nonvolatile memory element

Semiconductor device of an LDD structure having a floating gate

A flash-erase EEPROM cell with an asymmetric source and drain structure

Method of making semiconductor device with memory cells and peripheral transistors

Non-volatile semiconductor memory device erasing operation