Browsing by Author "Chen, TT"

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Continuous-wave high-power (320 mW) single mode operation of electronic vertically coupled InAs/GaAs quantum dot narrow-ridge-waveguide lasers
(2005-12-01)
Wang, JS
;
Lin, G
;
Hsiao, RS
;
Yang, CS
;
Lai, CM
High-power 3 mu m-wide narrow-ridge-waveguide lasers with ten stacks of electronic vertically coupled InAs/GaAs quantum dots in the active region were demonstrated. Unlike that from conventional uncoupled InAs quantum dot lasers, a narrow lasing spectrum was observed because the carriers tunneled in the vertical direction. Continuous-wave operation in single lateral mode yielded a kink-free output power of 320 mW with an efficiency of 0.46 W/A , and a sensitivity of lasing wavelength to temperature of 0.28 nm/K.
Nano-oxidation of silicon nitride films with an atomic force microscope: Chemical mapping, kinetics, and applications
(2001-02-15)
Chien, FSS
;
Chou, YC
;
Chen, TT
;
Hsieh, WF
;
Chao, TS
We demonstrate that local oxidation of silicon nitride films deposited on conductive substrates with a conductive-probe atomic force microscope (AFM) is a very promising approach for nanofabrication. Scanning Auger microscopy and spectroscopy are employed to verify the chemical changes after AFM-induced oxidation. Furthermore, the growth kinetics are found to have a logarithmic relationship of oxide height versus pulse duration [h proportional to ln(t/t(0))]. In contrast to rather slow thermal oxidation process, AFM-induced oxidation on silicon nitride has an anomalously high initial oxidation rate (similar to 30 000 nm/s at 10 V) and a small onset time t(0) (similar to 10 mus). As for the applications in ultrahigh-density recording, an oxide dot array (similar to 100 Gbit/in.(2)) produced by this process is demonstrated. The nitride film patterned by AFM can be utilized as an etching mask to fabricate "subtractive" silicon nanostructures, due to the large etching selectivity of Si3N4:SiO2:Si in various etchants. With this method, which is entirely compatible with the existing microelectronic processes, synthesis of ultrahigh packing density and ordered nanostructures could become readily achievable. (C) 2001 American Institute of Physics.
Nanomachining of (110)-oriented silicon by scanning probe lithography and anisotropic wet etching
(1999-10-18)
Chien, FSS
;
Wu, CL
;
Chou, YC
;
Chen, TT
;
Gwo, S
We have demonstrated that silicon nanostructures with high aspect ratios, having similar to 400 nm structural height and similar to 55 nm lateral dimension, may be fabricated by scanning probe lithography and aqueous KOH orientation-dependent etching on the H-passivated (110) Si wafer. The high spatial resolution of fabricated features is achieved by using the atomic force microscope based nano-oxidation process in ambient. Due to the large (110)/(111) anisotropic ratio of etch rate and the large Si/SiO2 etch selectivity at a relatively low etching temperature and an optimal KOH concentration, high-aspect-ratio gratings with (111)-oriented structural sidewalls as well as hexagonal etch pit structures determined by the terminal etch geometry can be obtained. (C) 1999 American Institute of Physics. [S0003-6951(99)03242-8].
Nanometer-scale conversion of Si3N4 to SiOx
(2000-01-17)
Chien, FSS
;
Chang, JW
;
Lin, SW
;
Chou, YC
;
Chen, TT
It has been found that atomic force microscope (AFM) induced local oxidation is an effective way for converting thin (< 5 nm) Si3N4 films to SiOx. The threshold voltage for the 4.2 nm film is as low as 5 V and the initial growth rate is on the order of 10(3) nm/s at 10 V. Micro-Auger analysis of the selectively oxidized region revealed the formation of SiOx. Due to the large chemical selectivity in various etchants and great thermal oxidation rate difference between Si3N4, SiO2, and Si, AFM patterning of Si3N4 films can be a promising method for fabricating nanoscale structures. (C) 2000 American Institute of Physics. [S0003-6951(00)03003-5].