Yamazaki S.,Semiconductor Energy Laboratory Co.
We have found that an IGZO film can exhibit a c-axis orientation by extremely highly purifying the oxide semiconductor. We call this IGZO as CAAC (C-Axis Aligned Crystal). CAAC structure can be achieved even on an amorphous and concave-convex surface. The CAAC structure has a crystal morphology in which a crystal grain boundary is not observed. By virtue of the CAAC structure, an off current Ioff is on the order of yA/μm (10-24 A/pm) even with a channel length of 0.45 um at a temperature of 85°C. This can be used for an ideal four-terminal switching element of a voltage input type having an on/off ratio of 20 digits or greater. Also, the temperature characteristics of Vg-Id are stable at temperatures ranging from -25°C to 150°C. We attempted to apply it to a normally-off CPU and FPGA with a small increase of F2 and a non-volatile memory without degradation. © The Electrochemical Society. Source
Semiconductor Energy Laboratory Co. | Date: 2013-07-02
Semiconductor Energy Laboratory Co. | Date: 2013-04-30
To provide a highly accurate temperature sensor circuit. The temperature sensor circuit includes a first constant current circuit; a first diode in which a first voltage reflecting the temperature of an object to be detected is generated between an anode and a cathode in accordance with a first current supplied from the first constant current circuit; a second constant current circuit; a second diode which includes an oxide semiconductor and in which a second voltage is generated between an anode and a cathode in accordance with a second current supplied from the second constant current circuit; and an amplifier circuit which amplifies a difference between the first voltage and the second voltage.
Semiconductor Energy Laboratory Co. | Date: 2014-03-05
To provide a battery leasing system with which an initial investment for a battery installed inside or outside a home of a user can be reduced, ideally to zero. To provide a leasing system in which the battery is installed at the users home with an initial investment of a leasing company and the user pays a predetermined charge to the leasing company. The amount of the predetermined charge collected from the user is a portion of money saved by energy conservation. This leasing system can easily increase homes with the battery capable of being as an emergency power source.
Semiconductor Energy Laboratory Co. | Date: 2013-05-07
An embodiment is to include a staggered (top gate structure) thin film transistor in which an oxide semiconductor film containing In, Ga, and Zn is used as a semiconductor layer and a buffer layer is provided between the semiconductor layer and a source and drain electrode layers. A metal oxide layer having higher carrier concentration than the semiconductor layer is provided intentionally as the buffer layer between the source and drain electrode layers and the semiconductor layer, whereby an ohmic contact is formed.