| 摘要(英) |
In this thesis, Germanium quantum dots (Ge QDs) which individually surrounded SiO2 were formed by using selective oxidation of poly-crystalline SiGe pillars over the Si3N4 layer on the Si-substrate and then Ge QDs would burrowed into Si3N4 and eventually touched Si-substrate. The high quality SiO2 of 3-4 nm in thickness between Ge-QD and Si, which solves 4.2% lattice mismatch in between QD and Si-substrate, can be employed as the dielectric layer in metal-oxide-semiconductor field effect transistor. As the top SiO2 was etched until Ge QDs exposed, Ge-QD/SiO2/Si-substrate MOS structure was fabricated. Accordingly Germanium quantum dot-gated photoMOSFET which possessed tremendous photo-electrical characteristics was then realized, etching the gate dielectric thickness leads to effective reduction on RC delay time constant.
Phototransistor with Ge QDs of 50 nm, 70 nm and 90 nm were fabricated, respectively, by the SiGe pillar size and time oxidation. The transistor had small subthreshold swing at darkness can be considered as a switch. Under illumination with wavelength of 850 nm and incident power of 4.38 mW, current enhancement of devices with Ge-QDs of 50 nm, 70 nm and 90 nm is 3.28×106, 2.39×106 , and 9.66×105 in off region and 8.23, 11.3, and 5.13 in on region respectively. Responsivity is 5.25 A/W, 6.26 A/W, and 6.6 A/W in off region and 1481 A/W, 2913 A/W, and 10597 A/W in on region were also observed showing great performance for near infrared ray.
In the end, we investigated the effect of the QD size. The device with smaller QD size would get better subthreshold swing and amplification without illumination. Under illumination, photo current and responsivity would increase with higher Ge content because of larger Ge-QD in off region. However, the device with small QD size was determined by its amplified ability and then compensated the effect of small QD size for less Ge content, getting better photo current and responsivity.
|
| 參考文獻 |
[1] https://en.wikipedia.org/wiki/Moore’s_law
[2] W. C. Dash et al., “Intrinsic optical absorption in single-crystal germanium and silicon at 77℃ and 300℃,” Physical Review, 99, 1151 (1955)
[3] J. E. Roth et al., “Optical modulator on Si employing Ge quantum wells,” Frontiersin Optics., 93, 191112 (2007)
[4] D. Ahn et al., “High performance, waveguide integrated Ge photodetectors,” Opt.Exp., 15, 3916 (2007)
[5] S. J. Koester et al., “Germanium on SOI infrared detectors for integrated photonic applications,” IEEE J. Sel. Topics Quantum Electron., 12, 1489 (2006)
[6] Roosevelt people, “Physics and application of GexSi1-x/Si strained-layer heterostructures,” IEEE Journal of Quantum Electronics, 22, 1696 (1986)
[7] F. K. LeGoues et al., “Anomalous strain relaxation in SiGe thin films and superlattices,” Physical review letters, 66, 2903 (1991)
[8] T. K. P. Luong et al., “Control of tensile strain and interdiffusion in Ge/Si(001) epilayers grown by molecular-beam epitaxy,” Physical review letters, 114, 83504 (2013)
[9] D. J. Eaglesham et al., “Dislocation-free Stranski-Krastanow growth of Ge onSi(100),” Physical review letters, 64, 1943 (1990)
[10] H.Kroemer, “Theory of a Wide-Gap Emitter for Transistors,” Proceedings of the IRE, 45, 1535 (1957)
[11] K.-W. Ang et al. “Low-voltage and high-responsivity germanium bipolar phototransistor for optical detections in the near-infrared regime,” IEEE Electron. Device Lett., 29, 1124 (2008)
[12] Y. Kang et al., “Monolithic germanium/silicon avalanche photodiodes with 340 GHz gain-bandwidth product,” Nat. Photon., 3, 59 (2009)
[13] S. Assefa et al., “Reinventing Germanium avalanche photodetector for nanophotonic on-chip optical interconnects,” Nature, 464, 80 (2010)
[14] J. Wang et al., “Silicon waveguide integrated germanium JFET photodetector with improved speed performance,” IEEE Photon. Technol. Lett., 23, 765 (2011)
[15] A. K. Okyay et al. “SiGe optoelectronic metal-oxide semiconductor field-effect transistor,” Opt Lett., 32, 2022 (2007)
[16] A. K. Okyay et al., “Silicon germanium CMOS optoelectronic switching device: Bringing light to latch,” IEEE Trans. Electron. Devices, 54, 3252 (2007)
[17] Ryan W. Going et al., “Germanium gate photoMOSFET integrated to silicon photonics,” IEEE Journal of Selected Topics in Quantum Electronics, 20, 4 (2014)
[18] T. Akatsu et al. “Germanium-on-insulator (GeOI) substrates—A novel engineered substrate for future high performance devices,” Proc.Mater. Sci. Semicond. Process., 9, 444 (2006)
[19] C. J. Tracy et al., “Germanium-on-insulator substrates by wafer bonding,” J. Electron. Mater., 33, 886 (2004)
[20] J. H. Nam et al., “Germanium on insulator (GOI) structure using hetero-epitaxial lateral overgrowth on silicon,” ECS Trans., 45, 203 (2012)
[21] Y. Liu, M. Deal, and J. Plummer, “Rapid melt growth of Germanium crystals with self-alignedmicrocrucibles on Si substrates,” J. Electrochem. Soc., 152, 688 (2005)
|
[Endnote RIS 格式]
[相關文章]
[文章引用]
[完整記錄]
[館藏目錄]
[檢視]
plurk
funp
live
udn
HD
myshare
netvibes
friend
youpush
delicious
baidu
Google bookmarks
del.icio.us
hemidemi
facebook
twitter
google
reddit