Search Results (78)

Si-based photonics has garnered considerable attention as a future device for complementary metal–oxide–semiconductor (CMOS) computing. However, few studies have investigated Si-based light sources highly compatible with Si ultra large-scale integration processing. In this study, we observed stable light emission at room temperature from superatom-like β–FeSi₂–core/Si–shell quantum dots (QDs). The β–FeSi₂–core/Si–shell QDs, with an areal density as high as ~10¹¹ cm⁻² were fabricated by self-aligned silicide process of Fe–silicide capped Si–QDs on ~3.0 nm SiO₂/n–Si (100) substrates, followed by SiH₄ exposure at 400 °C. From the room temperature photoluminescence characteristics, β–FeSi₂ core/Si–shell QDs can be regarded as active elements in optical applications because they offer the advantages of photonic signal processing capabilities and can be combined with electronic logic control and data storage. Full article

This work develops a novel compact Silicon-Controlled Rectifier (SCR) model incorporating self-heating effects, extending the conventional Ebers–Moll (E–M) framework for Bipolar Junction Transistors (BJTs) by comprehensively integrating parasitic effects. The temperature dependence of critical device parameters, including junction capacitances, emitter resistances, and saturation currents, is systematically characterized to accurately predict the device’s electrical behavior under Electrostatic Discharge (ESD) stress. Furthermore, a self-heating modeling approach is introduced based on the SCR layout characteristics. The impact of self-heating on SCR transient response was verified by comparing simulation results with measurements from SCR devices fabricated in a 0.18 µm Bipolar-CMOS-DMOS (BCD) process. Comparative analysis demonstrates superior accuracy over existing models. The proposed SCR model includes a complete definition of parameters and electrical relationships, ensuring compatibility with various Electronic Design Automation (EDA) platforms. Full article

Developing lead zirconate titanate (PZT)-based electro-optic (EO) modulators is vital for integrated photonics. The high annealing temperature required for the processing of PZT thin films restricts their compatibility with modern complementary metal–oxide–semiconductor (CMOS) technology. In this work, high-quality PZT films were fabricated on SiO₂/Si substrates at a low annealing temperature of 450 °C. The PZT films demonstrated a preferential (100) orientation and were uniform and crack-free. Based on the low-temperature PZT films, we subsequently designed and fabricated a Mach–Zehnder Interferometer (MZI) waveguide modulator. The measured half-wave voltage (V_π) was 4.8 V at a wavelength of 1550 nm, corresponding to an in-device EO coefficient as high as 66 pm/V, which shows potential use in optical devices. The results reported in this work show great promise for the integration of PZT thin films with other complex systems. Full article

To be CMOS-compatible, a low preparation temperature (<500 °C) for ferroelectric films is required. In this study, BiFeO₃ films were successfully fabricated at a low annealing temperature (<450 °C) on aluminum foils by a metal–organic decomposition process. The effect of the annealing atmosphere on the performance of BiFeO₃ films was assessed at 440 ± 5 °C. By using a N₂-rich atmosphere, a large remnant polarization (P_r~78.1 μC/cm² @ 1165.2 kV/cm), and a high rectangularity (~91.3% @ 1165.2 kV/cm) of the P-E loop, excellent charge-retaining ability of up to 1.0 × 10³ s and outstanding fatigue resistance after 1.0 × 10⁹ switching cycles could be observed. By adopting a N₂-rich atmosphere and aluminum foil substrates, acceptable electrical properties (P_r~70 μC/cm² @ 1118.1 kV/cm) of the BiFeO₃ films were achieved at the very low annealing temperature of 365 ± 5 °C. These results offer a new approach for lowering the annealing temperature for integrated ferroelectrics in high-density FeRAM applications. Full article

This paper reports on a CO₂ solidly mounted resonator (SMR)-based sensor with an integrated heater. The SMR device is CMOS compatible and operates at a resonant frequency of 2 GHz. To increase the sensitivity and selectivity, the SMR devices were functionalized with a 20 μm CO₂ sensitive layer. Two SMR sensors were employed in a differential configuration; one sensor was uncoated and used as a reference and the other was coated and used as a sensing device. The frequency shift of ~8 kHz/% CO₂ in dry air was observed after temperature and humidity compensation; demonstrating its potential application in indoor air quality (IAQ) monitoring. Full article

Industrial-grade optical semiconductor films have attracted considerable research interest because of their potential for wafer-scale mass deposition and direct integration with other optoelectronic wafers. The development of optical thin-film processes that are compatible with complementary metal-oxide-semiconductor (CMOS) processes will be beneficial for the improvement of chip integration. In this study, a multilayer periodically structured optical film containing Fabry–Perot cavity was designed, utilizing nine pairs of SiN/SiO₂ dielectrics. Subsequently, the multilayer films were deposited on Si substrates through the inductively coupled plasma chemical vapor deposition (ICPCVD) technique, maintaining a low temperature of 80 °C. The prepared films exhibit narrow bandpass characteristics with a maximum peak transmittance of 76% at 690 nm. Scanning electron microscopy (SEM) shows that the film structure has good periodicity. In addition, when the optical films are exposed to p/s polarized light at different angles of incidence, the cavity mode of the film undergoes a blueshift, which greatly affects the color appearance of the film. As the temperature rises, the cavity mode undergoes a gradual redshift, while the full width at half maximum (FWHM) and quality factor remain relatively constant. Full article

Although the von Neumann architecture-based computing system has been used for a long time, its limitations in data processing, energy consumption, etc. have led to research on various devices and circuit systems suitable for logic-in-memory (LiM) computing applications. In this paper, we analyze the temperature-dependent device and circuit characteristics of the floating gate field effect transistor (FGFET) source drain barrier (SDB) and FGFET central shallow barrier (CSB) identified in previous papers, and their applicability to LiM applications is specifically confirmed. These FGFETs have the advantage of being much more compatible with existing silicon-based complementary metal oxide semiconductor (CMOS) processes compared to devices using new materials such as ferroelectrics for LiM computing. Utilizing the 32 nm technology node, the leading-edge node where the planar metal oxide semiconductor field effect transistor structure is applied, FGFET devices were analyzed in TCAD, and an environment for analyzing circuits in HSPICE was established. To seamlessly connect FGFET-based devices and circuit analyses, compact models of FGFET-SDB and -CSBs were developed and applied to the design of ternary content-addressable memory (TCAM) and full adder (FA) circuits for LiM. In addition, depression and potential for application of FGFET devices to neural networks were analyzed. The temperature-dependent characteristics of the TCAM and FA circuits with FGFETs were analyzed as an indicator of energy and delay time, and the appropriate number of CSBs should be applied. Full article

Electrical double-layer (EDL) synaptic transistors based on organic materials exhibit low thermal and chemical stability and are thus incompatible with complementary metal oxide semiconductor (CMOS) processes involving high-temperature operations. This paper proposes organic–inorganic hybrid synaptic transistors using methyl silsesquioxane (MSQ) as the electrolyte. MSQ, derived from the combination of inorganic silsesquioxanes and the organic methyl (−CH₃) group, exhibits exceptional thermal and chemical stability, thus ensuring compatibility with CMOS processes. We fabricated Al/MSQ electrolyte/Pt capacitors, exhibiting a substantial capacitance of 1.89 µF/cm² at 10 Hz. MSQ-based EDL synaptic transistors demonstrated various synaptic behaviors, such as excitatory post-synaptic current, paired-pulse facilitation, signal pass filtering, and spike-number-dependent plasticity. Additionally, we validated synaptic functions such as information storage and synapse weight adjustment, simulating brain synaptic operations through potentiation and depression. Notably, these synaptic operations demonstrated stability over five continuous operation cycles. Lastly, we trained a multi-layer artificial deep neural network (DNN) using a handwritten Modified National Institute of Standards and Technology image dataset. The DNN achieved an impressive recognition rate of 92.28%. The prepared MSQ-based EDL synaptic transistors, with excellent thermal/chemical stability, synaptic functionality, and compatibility with CMOS processes, harbor tremendous potential as materials for next-generation artificial synapse components. Full article

The broad and fascinating properties of nanowires and their synthesis have attracted great attention as building blocks for functional devices at the nanoscale. Silicon and germanium are highly interesting materials due to their compatibility with standard CMOS technology. Their combination provides optimal templates for quantum applications, for which nanowires need to be of high quality, with carefully designed dimensions, crystal phase, and orientation. In this work, we present a detailed study on the growth kinetics of silicon (length 0.1–1 $\mathsf{\mu }$m, diameter 10–60 nm) and germanium (length 0.06–1 $\mathsf{\mu }$m, diameter 10–500 nm) nanowires grown by chemical vapor deposition applying the vapour–liquid–solid growth method catalysed by gold. The effects of temperature, partial pressure of the precursor gas, and different carrier gases are analysed via scanning electron microscopy. Argon as carrier gas enhances the growth rate at higher temperatures (120 nm/min for Ar and 48 nm/min H${}_2$), while hydrogen enhances it at lower temperatures (35 nm/min for H${}_2$ and 22 nm/min for Ar) due to lower heat capacity. Both materials exhibit two growth regimes as a function of the temperature. The tapering rate is about ten times lower for silicon nanowires than for germanium ones. Finally, we identify the optimal conditions for nucleation in the nanowire growth process. Full article

Advances in information technology are hindered by energy dissipation from Joule losses associated with charge transport. In contrast, the process of information based on spin waves propagation (magnons) in magnetic materials is dissipationless. Low damping of spin wave excitations is essential to control the propagation length of magnons. Ferrimagnetic Y₃Fe₅O₁₂ garnets (YIG) exhibit the lowest magnetic damping constants. However, to attain the lowest damping constant, epitaxial growth of YIG on single crystal substrates of Gd₃Ga₅O₁₂ at elevated temperatures is required, which hinders their CMOS integration in electronic devices. Furthermore, their low saturation magnetization and magnetocrystalline anisotropy are challenging for nanoscale device applications. In the search for alternative material systems, polycrystalline ferromagnetic Co₂₅Fe₇₅ alloy films and ferrimagnetic spinel ferrites, such as MgAl_0.5Fe_1.5O₄ (MAFO), have emerged as potential candidates. Their damping constants are comparable, although they are at least one order of magnitude higher than YIG’s. However, Co₂₅Fe₇₅ alloy thin film growth is CMOS compatible, and its magnon diffusion length is 20× longer than in MAFO. In addition, MAFO requires epitaxial growth on lattice-matched MgAl₂O₄ substrates. We discuss the material properties that control the Gilbert damping constant in Co_xFe_1−x alloys and MAFO and conclude that Co_xFe_1−x alloy thin films bring us closer to the realization of the exploitation of spin waves for magnonics. Full article

Temperature monitoring in extreme environments presents new challenges for MEMS sensors. Since aluminum nitride (AlN)/scandium aluminum nitride (ScAlN)-based surface acoustic wave (SAW) devices have a high Q-value, good temperature drift characteristics, and the ability to be compatible with CMOS, they have become some of the preferred devices for wireless passive temperature measurement. This paper presents the development of AlN/ScAlN SAW-based temperature sensors. Three methods were used to characterize the temperature characteristics of a thin-film SAW resonator, including direct measurement by GSG probe station, and indirect measurement by oscillation circuit and antenna. The temperature characteristics of the three methods in the range of 30–100 °C were studied. The experimental results show that the sensitivities obtained with the three schemes were −28.9 ppm/K, −33.6 ppm/K, and −29.3 ppm/K. The temperature sensor using the direct measurement method had the best linearity, with a value of 0.0019%, and highest accuracy at ±0.70 °C. Although there were differences in performance, the characteristics of the three SAW temperature sensors make them suitable for sensing in various complex environments. Full article

The use of composite materials has seen widespread adoption in modern aerospace industry. This has been facilitated due to their favourable mechanical characteristics, namely, low weight and high stiffness and strength. For broader implementation of those materials though, the out-of-autoclave production processes have to be optimized, to allow for higher reliability of the parts produced as well as cost reduction and improved production speed. This optimization can be achieved by monitoring and controlling resin filling and curing cycles. Photonic Integrated Circuits (PICs), and, in particular, Silicon Photonics, owing to their fast response, small size, ability to operate at higher temperatures, immunity to electromagnetic interference, and compatibility with CMOS fabrication techniques, can offer sensing solutions fulfilling the requirements for composite material production using carbon fibres. In this paper, we demonstrate a passive optical temperature sensor, based on a 220 nm height Silicon-on-Insulator platform, embedded in a composite tool used for producing RTM-6 composite parts of high quality (for use in the aerospace industry). The design methodology of the photonic circuit as well as the experimental results and comparison with the industry standard thermocouples during a thermal cycling of the tool are presented. The optical sensor exhibits high sensitivity (85 pm/°C), high linearity (R² = 0.944), and is compatible with the RTM-6 production process, operating up to 180 °C. Full article

Group-IV GeSn photodetectors (PDs) compatible with standard complementary metal–oxide-semiconductor (CMOS) processing have emerged as a new and non-toxic infrared detection technology to enable a wide range of infrared applications. The performance of GeSn PDs is highly dependent on the Sn composition and operation temperature. Here, we develop theoretical models to establish a simple rule of thumb, namely “GeSn−rule 23”, to describe GeSn PDs’ dark current density in terms of operation temperature, cutoff wavelength, and Sn composition. In addition, analysis of GeSn PDs’ performance shows that the responsivity, detectivity, and bandwidth are highly dependent on operation temperature. This rule provides a simple and convenient indicator for device developers to estimate the device performance at various conditions for practical applications. Full article

The electrical characteristics and resistive switching properties of memristive devices have been studied in a wide temperature range. The insulator and electrode materials of these devices (silicon oxide and titanium nitride, respectively) are fully compatible with conventional complementary metal-oxide-semiconductor (CMOS) fabrication processes. Silicon oxide is also obtained through the low-temperature chemical vapor deposition method. It is revealed that the as-fabricated devices do not require electroforming but their resistance state cannot be stored before thermal treatment. After the thermal treatment, the devices exhibit bipolar-type resistive switching with synaptic behavior. The conduction mechanisms in the device stack are associated with the effect of traps in the insulator, which form filaments in the places where the electric field is concentrated. The filaments shortcut the capacitance of the stack to different degrees in the high-resistance state (HRS) and in the low-resistance state (LRS). As a result, the electron transport possesses an activation nature with relatively low values of activation energy in an HRS. On the contrary, Ohm’s law and tunneling are observed in an LRS. CMOS-compatible materials and low-temperature fabrication techniques enable the easy integration of the studied resistive-switching devices with traditional analog–digital circuits to implement new-generation hardware neuromorphic systems. Full article

Recent advancements in quantum key distribution (QKD) protocols opened the chance to exploit nonlaser sources for their implementation. A possible solution might consist in erbium-doped light emitting diodes (LEDs), which are able to produce photons in the third communication window, with a wavelength around 1550 nm. Here, we present silicon LEDs based on the electroluminescence of Er:O complexes in Si. Such sources are fabricated with a fully-compatible CMOS process on a 220 nm-thick silicon-on-insulator (SOI) wafer, the common standard in silicon photonics. The implantation depth is tuned to match the center of the silicon layer. The erbium and oxygen co-doping ratio is tuned to optimize the electroluminescence signal. We fabricate a batch of Er:O diodes with surface areas ranging from 1 µm × 1 µm to 50 µm × 50 µm emitting 1550 nm photons at room temperature. We demonstrate emission rates around 5 × 10${}^6$ photons/s for a 1 µm × 1 µm device at room temperature using superconducting nanowire detectors cooled at 0.8 K. The demonstration of Er:O diodes integrated in the 220 nm SOI platform paves the way towards the creation of integrated silicon photon sources suitable for arbitrary-statistic-tolerant QKD protocols. Full article