RF Performance Research Articles

Automotive Grade WLCSP for Radar Applications

Wafer-Level Chip Scale Packages (WLCSPs) are becoming commonplace in the industry due to their small form factor. Applications include industrial and automotive which demand high reliability performance. Additionally, WLCSPs may be superior in some implementations to other package options for RF performance in the mmWave spectrum, which is desired for automotive radar application. In this study the industry’s first auto grade 1 capable large WLCSP package. (~ 72 mm2 body size, 18x15 BGA array, 0.5 mm pitch) will be presented. It will be demonstrated how extensive design enhancements, predictive simulations, careful package materials and process selection and assembly process optimization studies are required to develop a robust package solution. Multiple assembly process experiments and corner studies were conducted to demonstrate robustness of WLCSP package solution to meet automotive grade quality and reliability requirements. Both component/unit level and board level reliability was evaluated as per AECQ100 standards. Robustness margins were confirmed through reliability testing performed up to 2-3x reliability requirements.

Investigating temperature reliability of RF performance metrics and linearity for double gate doping less TFET

The Doping Less Tunnel Field Effect Transistor (DL-TFET) is gaining recognition as a promising TFET structure due to its resistance to random dopant fluctuations (RDFs) and the elimination of high thermal budgets and costly annealing techniques. However, temperature sensitivity remains a critical factor in assessing the device’s reliability, as the bandgap of the semiconductor material (E g ) varies with temperature fluctuations. Therefore, this study investigates the impact of temperature changes (ranging from 240 to 360 Kelvin) on the linearity and RF/analog characteristics of a Heterojunction (HJ), Double Gate (DG), Doping Less (DL) TFET.The analysis encompasses various RF/analog and DC parameters, including I D − V G characteristics, I D − V D characteristics, gm (transconductance), gd (output conductance), f T (cut-off frequency), GBP (Gain Bandwidth Product), TGF (transconductance generation factor), and TFP (transconductance frequency product). These parameters are evaluated using the ATLAS simulation tool, taking into account the influence of temperature fluctuations. Furthermore, the study considers temperature variations when assessing linearity characteristics such as the second-order Voltage Intercept Point (VIP2), third-order Voltage Intercept Point (VIP3), intermodulation distortion (IMD3), and third-order input-interception point (IIP3).

Implementation of Highly Reliable Contacts for RF MEMS Switches.

A contact is the key structure of RF MEMS (Radio Frequency Microelectromechanical System) switches, which has a direct impact on the switch's electrical and mechanical properties. In this paper, the implementation of highly reliable contacts for direct-contact RF MEMS switches is provided. As a soft metal material, gold has the advantages of low contact resistance, high chemical stability, and mature process preparation, so it is chosen as the metal material for the beam structure as well as the contacts of the switch. However, a Pt film is used in the bottom contact area to enhance the reliability of the contact. Three kinds of contacts with various shapes are fabricated using different processes. Particularly, a circular-shaped contact is obtained by dry/wet combined processes. The detailed fabrication process of the contacts as well as the Pt film on the bottom contact area are given. The experimental test shows that the contact shape has little effect on the RF performance of the switches. However, the circular contact shows better reliability than other contacts and can work well even after 1.2 × 109 cycles.

Low-resistive gate module for RF GaN-HFETs by electroplating

This paper presents a novel approach for reducing the gate resistance (R g) of K and Ka-band GaN HFETs with 150 nm gate length through a new gate metallization technique. The method involves increasing the gate cross-section via galvanic metallization using FBH’s Ir-sputter gate technology, which allows an increase in gate metal thickness from the current 0.4 μm to approximately 1.0 μm for the transistors under investigation. This optimization leads to a substantial 50% reduction in gate series resistance, resulting in significant improvements in the RF performance. Specifically, the devices achieve 20% higher output power density and 10% better power-added efficiency at 20 GHz and V ds = 20 V. The decreased gate resistance enables new degrees of freedom in design, such as longer gate fingers and/or shorter gate lengths, for more efficient power cells operating in this frequency range.

Design of a Ka-Band Heterogeneous Integrated T/R Module of Phased Array Antenna

The central element of a phased array antenna that performs beam electrical scanning, as well as signal transmission and reception, is the transceiver (T/R) module. Higher standards have been set for the integration, volume, power consumption, stability, and environmental adaptability of T/R modules due to the increased operating frequency of phased array antennas, the variability of application platforms, and the diversified development of system functions. Device-based multichannel T/R modules are the key to realizing low-profile Ka-band phased array antenna microsystem architecture. The design and implementation of a low-profile, high-performance, and highly integrated Ka-band phased array antenna T/R module are examined in this paper. Additionally, a dependable Ka-band four-channel T/R module based on Si/GaAs/Low Temperature Co-fired Ceramic (LTCC), applying multi-material heterogeneous integration architecture, is proposed and fabricated. The chip architecture, transceiver link, LTCC substrates, interconnect interface, and packaging are all taken into consideration when designing the T/R module. When compared to a standard phased array antenna, the module’s profile shrunk from 40 mm to 8 mm, and its overall dimensions are only 10.8 mm × 10 mm × 3 mm. It weighs 1 g, and with the same specs, the single channel volume was reduced by 95%. The T/R module has an output power of ≥26 dBm for single-channel transmission, an efficiency of ≥25%, and a noise factor of ≤4.4 dB. When compared to T/R modules based on System-on-Chip (SOC) devices, the RF performance has significantly improved, as seen by an increase in single channel output power and a decrease in the receiving noise factor. This work lays a foundation for the devitalization and engineering application of T/R modules in highly reliable application scenarios.

Numerical simulation of single-particle transients in low-noise amplifiers based on silicon-germanium heterojunction bipolar transistors and inverse-mode structures

In this work, TCAD simulation modeling is carried out for silicon-germanium heterojunction bipolar transistor (SiGe HBT), and an X-band low noise amplifier (LNA) circuit is built based on the SiGe HBT device model to carry out the hybrid simulation of single-particle transient (SET). The rule of SET pulse varying with LET value and incident angle of ions is studied, and the results show that with the increase of incident LET value, the amplitude of SET pulse at the LNA port increases, and the oscillation time is prolonged; with the increase of incident angle of ions, the amplitude of SET pulse at the LNA port first increases and then decreases, and the oscillation time decreases. With the development of the characterization process, the cutoff frequency (<i>f</i><sub>T</sub>) and the maximum oscillation frequency (<i>f</i><sub>MAX</sub>) of SiGe HBT device with IM structure, are measured considering the use of inverse-mode (IM) common emitter and common-base structures (Cascode) to reduce the sensitivity of the LNAs to single-particle effects. This work calibrates the devices of the TCAD platform as well as the devices of the ADS platform, establishes F-F LNAs as well as I-F LNAs on the ADS, respectively, and verifies the relevant RF performances of the LNA circuits by using the IM-structured SiGe HBTs as the core devices. The SET experiments are performed on the Sentaurus TCAD platform for the F-F LNA circuit and I-F LNA circuit for ions incident on two positions: common base transistor and common emitter transistor, respectively. It is concluded that the LNA with IM structure still shows good RF performance compared with the standard LNA at 130 nm. The transient current duration of the LNA circuit with IM Cascode structure is significantly reduced, and the peak value is reduced by 66% or more, which significantly reduces the sensitivity of the SiGe LNA circuit to SET.

RF Performance and TID Hardness Trade-offs in Annular 45-nm RF SOI CMOS Devices

RF Performance and TID Hardness Trade-offs in Annular 45-nm RF SOI CMOS Devices

Empirical Model and Experimental Validation of Meshed Ground Impact on RF Performance of Flexible Microstrip Lines for Bending Applications

Empirical Model and Experimental Validation of Meshed Ground Impact on RF Performance of Flexible Microstrip Lines for Bending Applications

Improvement of DC and RF characteristics for a novel AlGaAs/InGaAs HEMT with decreased single event effect

In order to promotion the RF performance, a grade In1-xGaxAs channel (G-HEMT) introduced to the AlGaAs/InGaAs HEMT. The G-HEMT with the grade In1-xGaxAs channel forms a deeper potential well and confines more electrons in the channel, results in improving the DC and RF characteristics. Moreover, because of the grade In1-xGaxAs is effectively reduced the peak electric field, and leads to a significant increase in breakdown voltage (BV). Moreover, the G-HEMT also increases resistance to single event effects (SEE). The simulation results indicate that the fmax is significantly increased to 889 GHz of G-HEMT from 616 GHz of conventional AlGaAs/InGaAs HEMT (C-HEMT). The the fT is significantly increased to 521 GHz of G-HEMT from 326 GHz of C-HEMT, as well as the IDsat is increased by 64.8% and the BV increases by 37%. In addition, the SEE peak drain current of G-HEMT is dramatically reduced 51%.

Improved RF Performances by Applying Asymmetric Passivation and Air-Bridged Field Plate in AlGaN/GaN HEMTs With Reliability-Based Simulation

Improved RF Performances by Applying Asymmetric Passivation and Air-Bridged Field Plate in AlGaN/GaN HEMTs With Reliability-Based Simulation

Tailoring RF Performance by Optimization of Reflector Boundary for Spacecraft Antenna

Tailoring RF Performance by Optimization of Reflector Boundary for Spacecraft Antenna

Experimental and Modeling Study of RF Performance of a Screen-Printed Coplanar Waveguide (CPW) up to 20 GHz under Monotonic Stretching

Experimental and Modeling Study of RF Performance of a Screen-Printed Coplanar Waveguide (CPW) up to 20 GHz under Monotonic Stretching

Classification of Roasted Coffee Beans with Principal Component Analysis and Random Forest

Roasted Robusta coffee beans originating from Toraja and Ciwidey, Indonesia have the same shape, color and characteristics of the coffee beans. There is often an error in recognizing coffee bean varieties just by looking with the naked eye. In terms of image classification, Random Forest has stable performance and performance. This research aims to classify coffee beans based on images of roasted coffee beans using the Random Forest and PCA algorithms. The steps taken were collecting Robusta and Toraja datasets which were taken manually and given 2000 labels. Data collection was carried out using a light intensity of 300 lux and a distance of 15 cm. The data was preprocessed, variables were reduced using PCA and Random Forest in forming the model. Testing uses 1600 training data and 400 test data to measure RF performance by changing the parameters of the number of data sets and the n value in Random Forest with the highest accuracy value of 98.05% with a value of n = 20 and 360 data tested.

Commissioning of MW class Gyrotron Test Facility at ITER-India & Demonstration of ITER relevant RF performance (1MW for 1000 s at 170 GHz)

ITER-India, as a part of its in-kind commitments to ITER project, has a mandate to deliver two “Gyrotron” based RF Source sets with state-of-the-art specifications (170 GHz, 1MW, 1000 s), for ECRH (Electron Cyclotron Resonance Heating) applications. With an aim to bench mark the integrated system performance, a MW class Gyrotron Test Facility has been developed at ITER-India under Phase-1 of the project execution plan. The facility has been developed with all necessary auxiliary systems and services such as the Low Voltage and High Voltage Power Supplies; Control, Protection and Monitoring Systems; RF Diagnostic Systems; Cooling and Vacuum Services etc. Further, a test Gyrotron with ITER relevant specifications (1MW, 170 GHz, 1000s) along with a set of dummy loads and waveguide components have been procured from M/s. Gycom, Russia, and fully integrated with the test facility. Detailed Site Acceptance Tests of the Test Gyrotron have been conducted at the newly developed ITER-India Gyrotron Test Facility (IIGTF). An output RF power of 1MW at 170 GHz for 1000 s with RF efficiency of about 50% has been successfully demonstrated during these tests there by validating the ITER relevant performance

RF Performance Benchmark of Nanosheets, Nanowires, FinFETs, and TreeFETs

RF Performance Benchmark of Nanosheets, Nanowires, FinFETs, and TreeFETs

Novel T-Shaped Gate Structure of AlGaN/GaN HEMTs on Si for RF Application

Due to the high electron saturation velocity and breakdown electric field, GaN-based high electron mobility transistors (HEMTs) have been widely used in high frequency and power application, such as telecommunication, satellite communication, and radar system [1]. Since first demonstration of AlGaN/GaN HEMTs in 1993 [2], the RF performance of these device has continuously improved by the progress on epitaxy and device scaling technology [3].The current gain cut-off frequency (fT) and the maximum oscillation frequency (fmax) from the small-signal equivalent circuit of the HEMT are derived by the following equations [4].From these equations, it can be concluded that in order to achieve high frequency operation, HEMTs should be designed with a T-shaped gate structure that simultaneously achieves low gate resistance (Rg) and low parasitic capacitance (Cgs and Cgd). However, there are complex fabrication processes to form the T-shaped gate. Typically, the T-shaped gate structure is implemented through electron beam lithography process using a tri-layer resist such as PMMA/PMGI/PMMA, which requires multiple exposures or developments. Multiple exposures can cause overlay errors that can significantly affect the T-shaped gate with smaller gate lengths [5]. Also, it is difficult to obtain an undercut structure that enables a good lift-off and guarantees a high yield due to the need for precise dose control. In addition, since the T-shaped gate has an unstable structure in which a narrow foot supports the weight of a wide head, the gate may collapse during a subsequent process.In this work, we fabricated a novel T-shaped gate using the negative e-beam resist HSQ, which offers a simple T-shaped gate fabrication process. The HSQ that was exposed to e-beam is located underneath the gate head and on both sides of the gate foot in our novel T-shaped gate design, providing a robust structure. The HSQ-assisted gate HEMTs exhibit comparable DC/RF performance compared to conventional T-shaped gate HEMTs. Acknowledgement This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MIST) (No. NRF-2021M3C13097672).

Improvement Attack Detection on Internet of Thinks Using Principal Component Analysis and Random Forest

Network security has become crucial in facing increasingly complex and sophisticated attack threats. Network intrusion detection aids in identifying suspicious activities indicating unauthorized intrusions. This research aims to enhance the performance of advanced attack detection. The Random Forest method is an algorithm that leverages an ensemble of decision trees. This ensemble comprises several independent decision trees used to classify data. One characteristic of the Random Forest method is its ability to address overfitting issues and provide good predictive quality. One approach to improving RF's performance is through Principal Component Analysis (PCA). PCA is a statistical technique used to reduce feature dimensionality. PCA eliminates feature correlations and identifies essential features that can enhance the detection of attacks and normal traffic. This research will be tested with the CIC IoT 2023 dataset, encompassing various attack types. The model testing consists of four feature dimensions, namely 5, 8, 10, and 47. The detection results are promising, significantly improving attack detection performance, reaching up to 99.2%.

Investigation of graded channel effect on analog/linearity parameter analysis of junctionless surrounded gate graded channel MOSFET

Linearity analysis of nanoscale devices is a vital issue as nonlinearity behavior is exhibited by them when employed in circuits for microwave and RF applications. In this work, a junctionless surrounded gate-graded channel MOSFET (JLSGGC MOSFET) is investigated thoroughly to analyze its linearity performance with the help of ATLAS tool of technology computer-aided design. The proposed device is compared systematically with the conventional junstionless surrounded gate MOSFET(JLSG MOSFET) to investigate their linearity. To evaluate the linearity, the figure of merits such as higher-order transconductance (Gm1, Gm2), intercept points(VIP2, VIP3, IIP3), IMD3 and 1 dB—compression point(P1 dB) are considered. The linearity of our proposed device improves by 35.5% in view of the compression point in comparison to JLSG MOSFET before the threshold voltage region of operation. The simulation results reveal a substantial enhancement in the linearity performance of the JLSGGC MOSFET. The improved linearity behavior of JLSGGC MOSFET makes it suitable for wireless RF and system-on-chip applications.Analog/RF performance is studied in terms of intrinsic gain (Gm/Gds), cut-off frequency (fT),maximum frequency of oscillation (fmax).Improved analog/RF performances of JLSGGC MOSFET suggests its applications in high frequency operating range.

Improving the RF Performance of InP DHBT Using fT-Doubler Technique

Improving the RF Performance of InP DHBT Using f_T-Doubler Technique

Electrical performance estimation and comparative study of heterojunction strained and conventional gate all around nanosheet field effect transistors

Abstract In this paper, we propose a novel type of Gate All Around Nanosheet Field Effect Transistor (GAA NS FET) that incorporates source heterojunctions and strained channels and substrate. We compare its electrical characteristics with those of the Heterojunction Gate All Around Nanosheet Field Effect Transistor (Heterojunction GAA NS FET) and the Conventional Gate All Around Nanosheet Field Effect Transistor (Conventional GAA NS FET). We investigate the impact of electrostatic control on both DC and analog parameters such as gate capacitance (C gg), transconductance g m, and cut-off frequency (f T) for all three device types. In our Proposed GAA NS FET, we employ Germanium for the source and substrate regions, Silicon/Germanium/Silicon (Si/Ge/Si) for the channel, and Silicon for the drain region. The introduction of strain into the nanosheet and the use of a heterojunction structure significantly enhance device performance. Before utilizing a model to analyze a semiconductor device, it is crucial to accurately determine and elaborate on the model parameters. In this case, we solve the Density Gradient (DG) equation self-consistently to obtain the electrostatic potential for a given electron Fermi-level distribution, use the Shockley-Read-Hall (SRH) equation to estimate carrier generation, account for bandgap narrowing in transport behavior, and consider auger recombination. Our general results indicate a notable improvement in drain current, transconductance, and unity-gain frequency by approximately 42%, 53%, and 31%, respectively. This enhancement results in superior RF performance for the Proposed GAA NS FET compared to both the heterojunction GAA NS FET and the conventional GAA NS FET.