The dependence of perpendicular magnetic anisotropy （PMA） on the barrier layer MgO thickness in MgO/CoFeB /Ta multilayers is investigated. The results show that the strongest PMA occurs in a small window of about 2 ...The dependence of perpendicular magnetic anisotropy （PMA） on the barrier layer MgO thickness in MgO/CoFeB /Ta multilayers is investigated. The results show that the strongest PMA occurs in a small window of about 2 4nm with the increase of MgO thickness from 1-1Onto. The crystalline degree of MgO and the change of interatomic distance along the out-of-plane direction may be the main reasons for the change of PMA in these multilayers. Moreover, the roughnesses of 2- and 4-nm-thick MgO samples are 3.163 and 1.8 nm, respectively, and both the samples show PMA. These results could be used to tune the magnetic characteristic of the ultra thin CoFeB film for future applications in perpendicular magnetic devices.展开更多
A detailed study of the magnetic characterizations of the top structure MgO/CoFeB/Mo is presented.The samples show strong perpendicular magnetic anisotropy（PMA） when the thickness of CoFeB is 0.9 nm and 1.1 nm.The s...A detailed study of the magnetic characterizations of the top structure MgO/CoFeB/Mo is presented.The samples show strong perpendicular magnetic anisotropy（PMA） when the thickness of CoFeB is 0.9 nm and 1.1 nm.The saturation magnetic moment and interface anisotropy constant are 1566 emu/cm3 and 3.75 erg/cm2,respectively.The magnetic dead layer（MDL） is about 0.23 nm in this system.Furthermore,strong capping layer thickness dependence is also observed.The strong PMA of 1.1 nm CoFeB only exists in a Mo cap layer thickness window of 1.2-2 nm.To maintain PMA,the metal layer could not be too thin or thick in these multilayers.The oxidation and diffusion of the metal capping layer should be respectively responsibility for the degradation of PMA in these thin or thick metal capping layer samples.展开更多
A 4-kbit low-cost one-time programmable （OTP） memory macro for embedded applications is designed and implemented in a 0.18-μm standard CMOS process. The area of the proposed 1.5 transistor （1.5T） OTP cell is 2.13...A 4-kbit low-cost one-time programmable （OTP） memory macro for embedded applications is designed and implemented in a 0.18-μm standard CMOS process. The area of the proposed 1.5 transistor （1.5T） OTP cell is 2.13 μm2, which is a 49.3% size reduction compared to the previously reported cells. The 1.5T cell is fabricated and measured and shows a large programming window without any disturbance. A novel high voltage switch （HVSW） circuit is also proposed to make sure the OTP macro, implemented in a standard CMOS process, works reliably with the high program voltage. The OTP macro is embedded in negative radio frequency identification （RFID） tags. The full chip size, including the analog front-end, digital controller and the 4-kbit OTP macro, is 600 × 600 μm2. The 4-kbit OTP macro only consumes 200 × 260 μm^2. The measurement shows a 100% program yield by adjusting the program time and has obvious advantages in the core area and power consumption compared to the reported 3T and 2T OTP cores.展开更多
This paper＂ describes and analyses the impact of the Ti layer, which is embedded between the insulator and top electrode, on the programming characteristic of the A1-HfO2-AI antifuse. The programming voltage of the a...This paper＂ describes and analyses the impact of the Ti layer, which is embedded between the insulator and top electrode, on the programming characteristic of the A1-HfO2-AI antifuse. The programming voltage of the antiiikse with 120 A HfO2 is properly reduced from 5.5 to 4.6 V with an embedded Ti layer. Low on-state resistance （-19Ω） and low programming voltage （4.6 V） is demonstrated in the embedded Ti antifhse with 120 A H fO2 while keeping sufficient off-state reliability. The antifuse embedded with a Ti layer between the insulator and top electrode has been developed and has potential in field programmable devices.展开更多
基金Supported by the National Basic Research Program of China under Grant No 2011CB921804the Beijing Key Subject Foundation of Condensed Matter Physics under Grant No 0114023
文摘The dependence of perpendicular magnetic anisotropy （PMA） on the barrier layer MgO thickness in MgO/CoFeB /Ta multilayers is investigated. The results show that the strongest PMA occurs in a small window of about 2 4nm with the increase of MgO thickness from 1-1Onto. The crystalline degree of MgO and the change of interatomic distance along the out-of-plane direction may be the main reasons for the change of PMA in these multilayers. Moreover, the roughnesses of 2- and 4-nm-thick MgO samples are 3.163 and 1.8 nm, respectively, and both the samples show PMA. These results could be used to tune the magnetic characteristic of the ultra thin CoFeB film for future applications in perpendicular magnetic devices.
基金Project supported by the National Fundamental Research Program of China(Grant No.2011CB921804)Beijing Key Subject Foundation of Condensed Matter Physics,China(Grant No.0114023)
文摘A detailed study of the magnetic characterizations of the top structure MgO/CoFeB/Mo is presented.The samples show strong perpendicular magnetic anisotropy（PMA） when the thickness of CoFeB is 0.9 nm and 1.1 nm.The saturation magnetic moment and interface anisotropy constant are 1566 emu/cm3 and 3.75 erg/cm2,respectively.The magnetic dead layer（MDL） is about 0.23 nm in this system.Furthermore,strong capping layer thickness dependence is also observed.The strong PMA of 1.1 nm CoFeB only exists in a Mo cap layer thickness window of 1.2-2 nm.To maintain PMA,the metal layer could not be too thin or thick in these multilayers.The oxidation and diffusion of the metal capping layer should be respectively responsibility for the degradation of PMA in these thin or thick metal capping layer samples.
文摘A 4-kbit low-cost one-time programmable （OTP） memory macro for embedded applications is designed and implemented in a 0.18-μm standard CMOS process. The area of the proposed 1.5 transistor （1.5T） OTP cell is 2.13 μm2, which is a 49.3% size reduction compared to the previously reported cells. The 1.5T cell is fabricated and measured and shows a large programming window without any disturbance. A novel high voltage switch （HVSW） circuit is also proposed to make sure the OTP macro, implemented in a standard CMOS process, works reliably with the high program voltage. The OTP macro is embedded in negative radio frequency identification （RFID） tags. The full chip size, including the analog front-end, digital controller and the 4-kbit OTP macro, is 600 × 600 μm2. The 4-kbit OTP macro only consumes 200 × 260 μm^2. The measurement shows a 100% program yield by adjusting the program time and has obvious advantages in the core area and power consumption compared to the reported 3T and 2T OTP cores.
文摘This paper＂ describes and analyses the impact of the Ti layer, which is embedded between the insulator and top electrode, on the programming characteristic of the A1-HfO2-AI antifuse. The programming voltage of the antiiikse with 120 A HfO2 is properly reduced from 5.5 to 4.6 V with an embedded Ti layer. Low on-state resistance （-19Ω） and low programming voltage （4.6 V） is demonstrated in the embedded Ti antifhse with 120 A H fO2 while keeping sufficient off-state reliability. The antifuse embedded with a Ti layer between the insulator and top electrode has been developed and has potential in field programmable devices.
