1-4hit |
Eun-Ki HONG Kyung Eun PARK Shun-ichiro OHMI
In this research, the effect of Ar/N2-plasma sputtering gas pressure on the LaBxNy tunnel and block layer was investigated for pentacene-based floating-gate memory with an amorphous rubrene (α-rubrene) passivation layer. The influence of α-rubrene passivation layer for memory characteristic was examined. The pentacene-based metal/insulator/metal/insulator/semiconductor (MIMIS) diode and organic field-effect transistor (OFET) were fabricated utilizing N-doped LaB6 metal layer and LaBxNy insulator with α-rubrene passivation layer at annealing temperature of 200°C. In the case of MIMIS diode, the leakage current density and the equivalent oxide thickness (EOT) were decreased from 1.2×10-2 A/cm2 to 1.1×10-7 A/cm2 and 3.5 nm to 3.1 nm, respectively, by decreasing the sputtering gas pressure from 0.47 Pa to 0.19 Pa. In the case of floating-gate type OFET with α-rubrene passivation layer, the larger memory window of 0.68 V was obtained with saturation mobility of 2.2×10-2 cm2/(V·s) and subthreshold swing of 199 mV/dec compared to the device without α-rubrene passivation layer.
Kyung Eun PARK Shun-ichiro OHMI
In this paper, the influence of high-temperature sputtering on the nitrogen-doped (N-doped) LaB6 thin film formation utilizing RF sputtering was investigated. The N-doped LaB6/SiO2/p-Si(100) MOS diode and N-doped LaB6/p-Si(100) of Schottky diode were fabricated. A 30 nm thick N-doped LaB6 thin film was deposited from room temperature (RT) to 150°C. It was found that the resistivity was decreased from 1.5 mΩcm to 0.8 mΩcm by increasing deposition temperature from RT to 150°C. The variation of work function was significantly decreased in case that N-doped LaB6 thin film deposited at 150°C. Furthermore, Schottky characteristic was observed by increasing deposition temperature to 150°C. In addition, the crystallinity of N-doped LaB6 thin film was improved by increasing deposition temperature.
Yasutaka MAEDA Mizuha HIROKI Shun-ichiro OHMI
In this study, the effect of nitrogen-doped (N-doped) LaB6 bottom-contact electrodes and interfacial layer (IL) on n-type pentacene-based organic field-effect transistor (OFET) was investigated. The scaled OFET was fabricated by using photolithography for bottom-contact electrodes. A 20-nm-thick N-doped LaB6 bottom-contact electrodes were formed on SiO2/n+-Si(100) substrate by RF sputtering followed by the surface treatment with sulfuric acid and hydrogen peroxide mixture (SPM) followed by diluted hydrofluoric acid (DHF; 1% HF) at room temperature (RT). Then, a 1.2-nm-thick N-doped LaB6 IL was deposited at RT. Finally, a 10-nm-thick pentacene film was deposited at 100°C followed by the Al back-gate electrode formation by using thermal evaporation. The current of electron injection was observed in the air due to the effect of surface treatment and N-doped LaB6 IL.
Yasutaka MAEDA Shun-ichiro OHMI Tetsuya GOTO Tadahiro OHMI
In this paper, the effect of a nitrogen-doped (N-doped) LaB6 interfacial layer (IL) on p-type pentacene-based OFET was investigated. The pentacene-based OFET with top-contact/back-gate geometry was fabricated. A 2-nm-thick N-doped LaB6 interfacial layer deposited on an 8-nm-thick SiO2 gate insulator. A 10-nm-thick pentacene film was deposited by thermal evaporation at 100°C followed by Au contact and Al back gate electrodes formation. The fabricated OFET showed normally- off characteristics and a steep subthreshold swing (SS) of 84 mV/dec. from ID-VG and ID-VD characteristics. Furthermore, the aging characteristics of 6 months after the fabrication were investigated and it was found that VTH and SS were stable when the N-doped LaB6 IL was introduced at the interface between SiO2 gate insulator and pentacene.