Lateral Diode Research Articles

Low V_pp, ultralow-energy, compact, high-speed silicon electro-optic modulator

We present a high-speed silicon optical modulator with a low V(pp) (peak-to-peak driving voltage) and ultralow energy consumption based on a microring resonator, with the refractive index modulation achieved by electric-field-induced carrier depletion in a reverse-biased lateral pn diode embedded in the ring structure. With a V(pp) of 2 V, we demonstrate a silicon modulator with a 3 dB bandwidth of 11 GHz, a modulation depth of 6.5 dB together with an insertion loss of 2 dB, ultralow energy consumption of 50 fJ per bit, and a small device active area of approximately 1000 microm(2).

Flexible microwave PIN diodes and switches employing transferrable single-crystal Si nanomembranes on plastic substrates

This paper reports the realization of flexible RF/microwave PIN diodes and switches using transferrable single-crystal Si nanomembranes (SiNM) that are monolithically integrated on low-cost, flexible plastic substrates. High frequency response is obtained through the realization of low parasitic resistance achieved with heavy ion implantation before nanomembrane release and transfer. The flexible lateral SiNM PIN diodes exhibit typical rectifying characteristics with insertion loss and isolation better than 0.9 dB and 19.6 dB, respectively, from DC to 5 GHz, as well as power handling up to 22.5 dBm without gain compression. A single-pole single-throw (SPST) flexible RF switch employing shunt-series PIN diode configuration has achieved insertion loss and isolation better than 0.6 dB and 22.9 dB, respectively, from DC to 5 GHz. Furthermore, the SPST microwave switch shows performance improvement and robustness under mechanical deformation conditions. The study demonstrates the considerable potential of using properly processed transferrable SiNM for microwave passive components. Future investigations on transferrable SiNMs will lead to eventual realization of monolithic microwave integrated systems on low-cost flexible substrates.

Nanodiamod lateral device field emission diode fabricated by electron beam lithography

Nitrogen incorporated nanodiamond film is known to aid in promoting enhanced electron emission via the induced graphitic behavior both in the bulk material and also the surface of the film. Since electron emission current is inversely proportional to the cathode to anode inter-electrode distance; it is necessary to implement electron beam lithography (EBL) to obtain a small emission gap. To achieve high resolution from EBL, a thinner nanodiamond film is required. In this work, we fabricated lateral field emitters on a 0.65 µm nanodiamond film. The nanodiamond film was deposited onto a silicon-on-insulator (SOI) substrate in CH 4/H 2/N 2 plasma ambient by microwave chemical vapor deposition. The SOI was prepared for diamond nucleation using mechanical abrasion and ultrasonication in nanodiamond powder. Electron beam lithography (EBL) was used to delineate a 10 emitter tipped diode with a 2 µm anode-to- anode emission gap.

Diamond Vacuum Electronic Device Behavior After High Neutron Fluence Exposure

This paper reports the first neutron exposure on diamond electronic test structures for their possible application in very high fluence neutron conditions. The behavior of diamond lateral emission diodes after high neutron fluence of 4.4times10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">13</sup> neutrons/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> is evaluated. No noticeable changes in the device structure and electrical behavior, specifically resistivity, dilation and emission characteristics were observed.

Recent Progress in High-Speed Silicon-Based Optical Modulators

The evolution of silicon optical modulators is recalled, from the first effect demonstrations to the characterization of high-performance devices integrated in optical waveguides. Among possibilities to achieve optical modulation in silicon-based materials, the carrier depletion effect has demonstrated good capacities. Carrier depletion in Si and SiGe/Si structures has been theoretically and experimentally investigated. Large phase modulation efficiency, low optical loss, and large cutoff frequency are obtained by considering simultaneously optical and electrical structure performances. Integrated Mach-Zehnder interferometers and resonators are compared to convert phase modulation into intensity modulation. Finally, recent results on high-speed and low-loss silicon optical modulator using an asymmetric Mach-Zehnder interferometer are presented. It is based on a p-doped slit embedded in the intrinsic region of a lateral pin diode integrated in a silicon-on-insulator waveguide. This design allows a good overlap between the optical mode and carrier density variations. An insertion loss of 5 dB has been measured with a -3 dB bandwidth of 15 GHz.

Growth of InAs/InP-based quantum dots for 1.55 μm laser applications

Photoluminescence and scanning electron microscopy have been used to study the growth of InAs quantum dots with InGaAsP barriers on (0 0 1) InP substrates for 1.55 μm laser applications. The effect of growing quantum dots on a thin GaP layer as well as the use of a two step dot capping procedure was investigated, optimising for dot density, emission energy, and photoluminescence emission full-width half-maximum. It was found that the emission energy of a dot layer could be tuned around the important 1.55 μm wavelength range while maintaining a high dot density and narrow dot size distribution, even when stacking multiple layers. An optimised dot structure was then used as the core of a single lateral mode laser diode demonstrating continuous wave operation at room temperature with a threshold of 25.9 mA and slope efficiency of 0.3 A/W.

Development of a vacuum packaged nanodiamond lateral field emission device

The authors report the development of a monolithic diamond field emission device in lateral configuration operating in a vacuum package. Nanocrystalline diamond is applied in the microfabrication of planar lateral emitter diodes on a silicon-on-insulator substrate. A feasible packaging process has been developed for the device, where the diodes are die attached, wire bonded, and vacuum sealed in a cavity package. Field emission characterization measurements performed on the packaged diamond lateral vacuum devices indicate a practical construct and package for vacuum micro/nanoelectronic applications.

Surface potential of functionalised nanodiamond layers

AbstractCarbon nanomaterials especially ultrananocrystalline diamond and nanocrystalline diamond films have attracted more and more interest due to their unique electrical, optical and mechanical properties, which make them widely used for different applications (e.g. MEMS devices, lateral field emission diodes, biosensors and thermoelectrics). Nanocrystalline diamond can also offer novel advantages for drug delivery development. Recent studies have begun to use nanocrystalline diamond for in-vivo molecular imaging and bio-labeling. To enable grafting of complex bio-molecules (e.g. DNA) the surface of ND requires specific fictionalization (e.g. H, OH, COOH &amp; NH2). Due to the surface dipoles of functionalised nanodiamond band bending at the surface can be easily induced and from the measured band bending we can deduce the type of the fictionalization on the surface. The surface potential of H-terminated and OH terminated nanodiamond layers was investigated by Kelvin probe microscope. From the change of the surface potential value (as the departure of the material surface from the state of electrical neutrality is reflected in the energy band bending) the work function of the H-terminated nanodiamond layer was established to be lower than OH-terminated nanodiamond layer. The surface potential difference can be explained by the surface dipole induced by the electro-negativity difference between the termination atoms.

The effect of interelectrode spacing on field emission in nanodiamond lateral vacuum devices

Nitrogen-incorporated nanocrystalline diamond, offering a high field enhancement factor ( β), has been applied in the development of monolithic lateral emitter diodes. The dependence of the emission current on the interelectrode spacing in the device structure has been investigated. Three batch-fabricated devices, incorporating a 125-fingered nanodiamond lateral emitter array, with different interelectrode spacings of 4 μm, 7 μm and 10.5 μm defined by lithography, were characterized for field emission. The effect of changing the anode–cathode gap was observed in the I– V characteristics, with a distinct reduction in the device turn-on and operating voltages with a decrease in the gap, inversely altering the electric field at the emitter fingers. The nanodiamond emitter devices demonstrate the same low turn-on electric field ( E) of ∼ 2 V/μm and closely matched I– E characteristics. The scaling behavior of the emission current with the interelectrode spacing can be studied at a given applied electric field. For example, at ∼ 8 V/μm, which corresponds to anode voltages of 85 V, 55 V, and 30 V for the 10.5 μm, 7 μm and 4 μm lateral gap devices respectively, the extracted emission current is 5.1 μA. A strong sensitivity of 10 V µm − 1 observed in the field emission behavior of the nanodiamond lateral device as a function of the cathode-anode distance can be utilized in the development of novel sensors and NEMS, reliably operable in harsh environments of temperature and radiation.

Low loss and high speed silicon optical modulator based on a lateral carrier depletion structure

A high speed and low loss silicon optical modulator based on carrier depletion has been made using an original structure consisting of a p-doped slit embedded in the intrinsic region of a lateral pin diode. This design allows a good overlap between the optical mode and carrier density variations. Insertion loss of 5 dB has been measured with a contrast ratio of 14 dB for a 3 dB bandwidth of 10 GHz.

Nanodiamond lateral field emitter devices on thick insulator substrates for reliable high power applications

Nanocrystalline diamond field emitter array devices on a thick insulator substrate are being developed for high power applications. These monolithic lateral emitter diodes in comb array configurations demonstrate potential for high emission current applications. A 640 μm-thick aluminium nitride insulating substrate has been integrated with nanodiamond for device electrode isolation. The fabrication process and preliminary field emission characterization results are discussed. The nanodiamond lateral vacuum device may be a superior way to achieve reliable high-speed and high-power electronics.

Field emission devices for advanced electronics comprised of lateral nanodiamond or carbon nanotube emitters

Nanocarbon-derived electron emission devices, specifically, nanodiamond lateral field emission diodes and gated carbon nanotube triodes are new configurations for robust nanoelectronic devices. These novel micro/nanostructures provide an alternative and efficient means of accomplishing electronics that are impervious to temperature and radiation. Nitrogen-incorporated nanocrystalline diamond has been lithographically micropatterned to utilize the material as an electron field emitter. Arrays of laterally arranged “finger-like” nanodiamond emitters constitute the cathode in a versatile diode configuration with small interelectrode separation. Nanodiamond lateral tip conditioning techniques are employed to improve emission and the subsequent device performance discussed. A low diode turn-on voltage of 7 V and a high emission current of 90 μA at an anode voltage of 70 V (electric field of ∼ 7 V/μm) is reported for the nanodiamond lateral device. Also, the development of a field emission triode amplifier based on aligned carbon nanotubes (CNTs) with low turn-on voltage and small gate leakage current, utilizing a dual-mask microfabrication process is reported. The2 × 20 μm CNT triode array displays a gate turn-on voltage of ∼ 44 V, and low gate currents less than 3% of the anode currents. The low gate leakage currents observed confirmed the effectiveness of the convex-shaped gated CNT emitter in alleviating the cathode-gate leakage problem that compromises the operation of a field emission triode.

P‐198L: Late‐News Poster: Integrated Ambient Light Sensor in LTPS AMLCDs

AbstractSensing ambient light in mobile applications allows reduced power consumption through backlight control. Integration of light sensors reduces module complexity and location of the sensors close to the pixel array simplifies integration in products. We describe an integrated ambient light sensor consisting of lateral pin diodes and digital read out circuit.

A New Silicon-on-Insulator Lateral Insulated Gate Bipolar Transistor and Lateral Diode Employing the Separated Schottky Anode for a Power Integrated Circuit

A new silicon-on-insulator (SOI) lateral insulated gate bipolar transistor (LIGBT) and lateral diode employing the separated Schottky anode (SSCA) is proposed and verified by the two dimensional numerical simulation based on experimental results. The Schottky barrier between the aluminum and lightly doped n-type silicon (Al/n-Si) of SSCA provides the potential difference between the n- anode contact and p+ anode to enhance the hole injection of p+ anode, which improves the forward current–voltage (I–V) characteristics. The anode region of SSCA-LIGBT is successfully decreased without negative differential resistance (NDR) regime and sacrificing the switching speed by employing contact. The SSCA structure applied to the diode also considerably improves the reverse recovery compared to the conventional p–i–n diode and reverse blocking capability compared to conventional Schottky diode.

Nanocrystalline diamond lateral field emission diode fabrication by dual micropatterning technique

A dual-mask micropatterning process has been developed to fabricate nanocrystalline diamond lateral field emission diode with reduced reversed leakage current. In contrast to the all-diamond lateral device reported previously, this vacuum microelectronic device integrates a 6-finger lateral nanodiamond emitter cathode with a nickel metal anode on a SiO2 underlying substrate serving as the spacer material. In this configuration, the nitrogen-incorporated nanodiamond cathode has higher field enhancement factor, geometrically as well as materially, resulting in high rectification and excellent diode behavior. This lateral device processing further illustrates the viability of nanocrystalline diamond for device integration.

Nanodiamond lateral comb array field emission diode for high current applications

Nanodiamond comb-shaped lateral field emitter arrays in diode configuration were fabricated and characterized for high current field emission. Nitrogen-incorporated nanocrystalline diamond with grain size of 5–10 nm was micropatterned using RIE to realize interconnected arrays of comb structures equipped with uniformly spaced high aspect ratio lateral emitter fingers. A 9000-fingered nanodiamond lateral comb array diode with an inter-electrode spacing of 8 μm demonstrated a high emission current of ∼ 25 mA at an anode voltage of 260 V (electric field ∼ 32 V/μm) in 10 − 7 Torr vacuum. The lateral emitter configuration shows potential for higher power with no emission current saturation observed. These vacuum micro/nanoelectronic devices comprised of nanodiamond lateral field emission diodes are attractive for low-voltage operating high current electron sources, high-power and high-speed switches, and other extreme demand/extreme environment electronics.

Nanocarbon field emission devices

AbstractWe are fabricating and examining nanocarbon derived electron emission devices, specifically, nanodiamond lateral field emission diodes and gated carbon nanotube triodes. These novel microstructures provide interesting means of accomplishing electronics that are unaffected by temperature and radiation. (© 2006 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

ESD Protection for SOI Technology Using Under-the-BOX (Substrate) Diode Structure

This paper presents a new integrated silicon-on-insulator (SOI) substrate-diode (SUBD) structure for an electrostatic-discharge (ESD) protection of the SOI I/O circuits. The diode is built under the buried oxide, within the substrate region of the SOI wafer, without additional steps to the conventional SOI CMOS process. This paper shows that the ESD protection level can reach four times the level of the standard SOI lateral-diode structure. This paper presents the device and process simulation results to demonstrate the effect of self-heating in both the standard SOI lateral and substrate diodes, and to demonstrate how to optimize the SUBD structure using a deep n-well implant

Suppression of Leakage Current of Ni/Au Schottky Barrier Diode Fabricated on AlGaN/GaN Heterostructure by Oxidation

We have proposed and fabricated a lateral GaN Schottky barrier diode (SBD) that increases the breakdown voltage and decreases the leakage current by the oxidation of a Ni/Au Schottky contact. After an oxidation, the anode current was increased under a high anode bias, whereas the turn-on voltage was slightly increased. The leakage current was considerably decreased to less than 1 nA after the oxidations of 5 and 10 min. A high breakdown voltage of 750 V was measured in the proposed GaN SBD when multiple floating metal rings (FMRs) were used for edge termination and oxidation was employed. We have also measured the reverse recovery waveforms at room temperature and 125 °C and the fabricated GaN SBDs show very fast reverse recovery characteristics.

Simulation of vertical and lateral ZnO light-emitting diodes

All-ZnO light-emitting diodes (LEDs) offer the promise of a low-cost, brighter alternative to existing GaN-based light emitters for solid-state lighting applications, in part due to the higher exciton binding energy of ZnO. We have used ISE TCAD™ simulations to examine the effect of active, n- and p-layer dopings and thicknesses on the optical output intensity and current-voltage characteristics of both vertical and lateral geometry ZnO LEDs. The latter geometry is attractive for ultralow structures with the ZnO deposited on glass substrates. The current density distribution is more uniform in the vertical structures but there is little difference in optical output power as a function of doping or layer thickness between the two geometries.