Emerging telecommunication and data routing applications anticipate a photonic roadmap leading to ultra-compact photonic integrated circuits. Consequently, photonic devices will soon have to meet footprint and efficiency requirements similar to their electronic counterparts calling for extreme capabilities to create, guide, modulate, and detect deep-subwavelength optical fields. For active devices such as modulators, this means fulfilling optical switching operations within light propagation distances of just a few wavelengths. Plasmonics, or metal optics, has emerged as one potential solution for integrated on-chip circuits that can combine both high operational speeds and ultra-compact architectures rivaling electronics in both speed and critical feature sizes. This article describes the current status, challenges, and future directions of the various components required to realize plasmonic integrated circuitry.

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Toward integrated plasmonic circuits

A photoelectric conversion device comprises: a plurality of photoelectric conversion elements each having a photo-sensing surface; insulation films; a plurality of light-guiding portions arranged above the insulation films, each of the plurality of light-guiding portions guiding light on the photo-sensing surface of each of the plurality of photoelectric conversion elements; and boundary portions, each of the boundary portions defines a boundary between the adjacent light-guiding portions and is formed of a material lower in refractive index than a material that forms the plurality of light-guiding portions, wherein a width of each of the boundary portions is not more than half a shortest wavelength in a wavelength range of visible light, and a height from a lower surface to an upper surface of each of the plurality of light-guiding portions is not less than double a longest wavelength in the wavelength range of visible light.

Photoelectric conversion device and imaging system

The major radiation of the sun can be roughly divided into three regions: ultraviolet, visible, and infrared light. Detection in these three regions is important to human beings. The metal-insulator-semiconductor photodetector, with a simpler process than the pn-junction photodetector and a lower dark current than the MSM photodetector, has been developed for light detection in these three regions. Ideal UV photodetectors with high UV-to-visible rejection ratio could be demonstrated with III-V metal-insulator-semiconductor UV photodetectors. The visible-light detection and near-infrared optical communications have been implemented with Si and Ge metal-insulator-semiconductor photodetectors. For mid- and long-wavelength infrared detection, metal-insulator-semiconductor SiGe/Si quantum dot infrared photodetectors have been developed, and the detection spectrum covers atmospheric transmission windows.

https://www.mdpi.com/1424-8220/10/10/8797/pdf

Metal-insulator-semiconductor photodetectors.

p-Si/n-CdS radial heterojunction nanowires have been grown by pulse laser deposition of CdS on vertically aligned Si nanowires fabricated using a room temperature wafer-scale etching of p-type Si. Temperature-dependent photoluminescence characteristics have been studied in detail in the blue–green–red regions from these p-Si/n-CdS core–shell nanowires. The photocurrent spectra of the nanowire heterojunctions have been investigated at room temperature to study the spectral responsivity and detectivity of the core–shell nanowire diodes. The peak responsivity (1.37 A/W) and detectivity (4.39 × 1011 cm Hz1/2/W) at −1 V show the potential of the nanoscaled devices for the high efficiency photodetectors in the visible–near-infrared spectrum.

High Efficiency Si/CdS Radial Nanowire Heterojunction Photodetectors Using Etched Si Nanowire Templates

Applying stress to induce appropriate strain in the channel region of metal-oxide-semiconductor field effect transistors (MOSFETs) increases both electron and hole mobilities in the strained channel as stated in R People (1986), J J Welser et al (1994), C K Maiti et al (1998) and D J Paul (2004) Furthermore, interest is driven by the possibility of creating electronic devices as well as integrating existing devices in different materials systems, leading to the production of integrated circuits with increased functionality and lower cost In this article, we review various mobility enhancement techniques, such as substrate-enhancement, including stain, Ge/SiGe channels, orientations, process-induced strain, and package-strain (external mechanical strain)

Mobility-enhancement technologies

The flicker noise characteristics of strained-Si nMOSFETs are significantly dependent on the gate oxide formation. At high temperature (900/spl deg/C) thermal oxidation, the Si interstitials at the Si/oxide interface were injected into the underneath Si-SiGe heterojunction, and enhanced the Ge outdiffusion into the Si/oxide interface. The Ge atoms at Si/oxide interface act as trap centers, and the strained-Si nMOSFET with thermal gate oxide yields a much larger flicker noise than the control Si device. The Ge outdiffusion is suppressed for the device with the low temperature (700/spl deg/C) tetraethylorthosilicate gate oxide. The capacitance-voltage measurements of the strained-Si devices with thermal oxide also show that the Si/oxide interface trap density increases and the Si-SiGe heterojunction is smeared out due to the Ge outdiffusion.

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Ge outdiffusion effect on flicker noise in strained-Si nMOSFETs

A Ge quantum dot photodetector has been demonstrated using a metal-oxide-semiconductor (MOS) tunneling structure. The oxide film was grown by liquid phase deposition (LPD) at 50/spl deg/C. The photodetector with five-period Ge quantum dot has responsivity of 130, 0.16, and 0.08 mA/W at wavelengths of 820 nm, 1300 nm, and 1550 nm, respectively. The device with 20-period Ge quantum dot shows responsivity of 600 mA/W at the wavelength of 850 nm. The room temperature dark current density is as low as 0.06 mA/cm/sup 2/. The high performance of the photodetectors at 820 nm makes it feasible to integrate electrooptical devices into Si chips for short-range optical communication.

A high efficient 820 nm MOS Ge quantum dot photodetector

The correlations between the threading dislocations and the low-frequency noise characteristics of the n-type strained-Si field-effect transistors are studied using the devices with different sizes. The device-area-dependent S/sub VG/ (power spectral density of the gate referred voltage noise) ratio of the strained-Si devices over the control Si devices obtained form geometric average can be understood by the modified carrier number fluctuation model with excess traps from the Poisson distributed threading dislocations. The equivalent trap number per threading dislocation extracted from the area-dependent S/sub VG/ ratios is /spl sim/85 for the strained-Si devices, and which results in /spl sim/4.2X degradation of the S/sub VG/ for the strained-Si device with the device area of 625 /spl mu/m/sup 2/.

Threading dislocation induced low frequency noise in strained-Si nMOSFETs

The metal-insulator-semiconductor (MIS) Ge-Si quantum-dot infrared photodetectors (QDIPs) are successfully demonstrated. Using oxynitride as gate dielectric instead of oxide, the operating temperature reaches 140 and 200 K for 3-10 and 2-3 /spl mu/m detection, respectively. From the photoluminescence spectrum, the quantum-dot structures are responsible for the 2-3 /spl mu/m response with high operation temperature, and the wetting layer structures may be responsible for the 3-10 /spl mu/m response. This novel MIS Ge-Si QDIP can increase the functionality of Si chip such as noncontact temperature sensing and is compatible with ultra-large scale integration technology.

Novel MIS Ge-Si quantum-dot infrared photodetectors

buffer layer of 0.6 nmcan be achieved. The novel cleaning solutions with various surfactants and chelating agents for post-CMP SiGe were studied.There was about 10% current enhancement of the optimal cleaning conditions, showing high performance in particle removal,metallic cleaning, and electrical characteristics.© 2005 The Electrochemical Society. DOI: 10.1149/1.2149291 All rights reserved.Manuscript submitted February 22, 2005; revised manuscript received October 11, 2005.Available electronically December 30, 2005.

https://ir.nctu.edu.tw:443/bitstream/11536/12859/1/000234543400063.pdf

P.S. Chen

Papers

Ge outdiffusion effect on flicker noise in strained-Si nMOSFETs

A high efficient 820 nm MOS Ge quantum dot photodetector

Threading dislocation induced low frequency noise in strained-Si nMOSFETs

Novel MIS Ge-Si quantum-dot infrared photodetectors

The CMP Process and Cleaning Solution for Planarization of Strain-Relaxed SiGe Virtual Substrates in MOSFET Applications