This paper describes the implementation of low-power, low-phase-noise (PN), and robust startup tailless class-C voltage-controlled oscillator (TVCO) for 5G new radio (NR) technology. It features dual gate voltage control source biasing to generate fast startup and differential signal amplitude balancing, thus eliminating the requirement of the conventional tail current source, which introduces more parasitic capacitance that affects the oscillation frequency, phase noise, and power consumption. The TVCO is fabricated in 180 nm complementary metal-oxide semiconductor (CMOS) technology, oscillating at 2.59 GHz 5G NR carrier frequency with an output voltage swing of 1.7 V and low-phase-noise of -122 dBc/Hz at 1 MHz offset with supply voltage headroom of 0.7 V. Without additional features added, the TVCO consumes very low-power and a small die area of 0.98 mW and 0.49 mm2, respectively. The achieved figure of merit (FoM) is 190.36 dBc/Hz.

This paper describes a low power, low phase noise CMOS voltage controlled oscillator (VCO) with a cascoded cross-coupled pair (XCP) configuration for high data rate 5G New Radio (5G-NR) applications. The core consists of a primary auxiliary VCO built as a negative conductance circuit to improve phase noise and a secondary core with a cascoded formation to increase output voltage swing. A switched varactor array (SVA) wideband tuner is integrated for a wide bandwidth application in a low power implementation. The dual-core VCO was designed in CMOS 130 nm technology and occupies only 1.05 mm2 of space. With a supply voltage of 1.2 V, the VCO achieved a tuning range of 32.43% from 3.45 GHz to 4.47 GHz. At 3.96 GHz carrier center frequency with 1 MHz offset, the total power consumption is 0.7 mW with a corresponding phase noise (PN) of −121.25 dBc/Hz and a Figure of Merit (FoM) of 193.25 dBc/Hz. The results are validated using Cadence Spectra RF simulations.

This paper demonstrates the design of integrated 8-bit pipelined ADC and DAC for Bluetooth Low Energy (BLE) system. The op-amp has provided sufficient open-loop DC gain to guarantee the excellent performance of ADC. While the hybrid DAC, which has been partitioned equally into two sub-segments, i.e. current-steering and binary-weighted resistor architectures operated with low power consumption and maintained good performance. This design has been performed using Silterra 180 nm CMOS process technology with the supplied voltage of 1.8 V. The silicon area is 3.02 mm2. Post-layout simulation results exhibited the integrated ADC and DAC have integral non-linearity (INL) errors of −1.0/+0.5 LSB and −1.0/+1.0 LSB, respectively and consumed 39.6 mW for data conversion.

Radio-frequency (RF) magnetron sputtering is one of the methods to deposit thin films that have been widely used in the deposition of GaN thin films to fabricate optoelectronic devices. However, the crystallisation of the GaN films deposited using RF magnetron sputtering at room temperature shows GaN amorphous structure. Therefore, post-annealed method at temperature 950°C in N2 condition using CVD furnace is applied after GaN thin film was deposited on Si (111) with and without AlN buffer layer by RF magnetron sputtering at room temperature. Here we report the discovery and characterisation of the GaN thin films after post-annealing at 950°C in nitrogen ambient with and without AlN as a buffer layer. X-ray diffraction (XRD) is used to identify the crystal phase of GaN thin films. The surface morphology including thickness, surface roughness and grain size is studied by field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). The analyses of XRD show the amorphous structure for the GaN thin films with and without AlN buffer layer that does not undergo post-annealing. After undergoing post-annealing, it does not show any crystalline structure of GaN but crystalline structure of gallium oxide (Ga2O3) dominantly exists in the GaN thin film without AlN buffer layer. AFM analysis shows the grain size and the surface roughness for GaN thin film without AlN buffer layer increases after annealing which are 50.15 nm and 0.87 nm compared with before annealing which are 43.42 nm and 0.61 nm respectively. However, the grain size and surface roughness for GaN films without buffer layer are lower compared with GaN films with the AlN buffer layer even after post-annealing process which are 98.13 nm and 1.30 nm, respectively.

To date, the deposition of AlGaN thin film using the co-sputtering technique at room temperature has not been reported yet. The use of AlGaN for electronic devices has been widely known because of its ultra-wide bandgap. However, to deposit the AlGaN thin film and achieved high quality of AlGaN films, higher temperature or extra time deposition are needed, which is not compatible with industrial fabrication process. Here, a co-sputtering technique between two power supplies of magnetron sputtering (which are RF and HiPIMS) is introduced to deposit the AlGaN thin films. The AlGaN thin films were deposited at various RF power to study their effect on structural properties and morphology of the thin films. AlGaN films were sputtered simultaneously on silicon (111) substrate for short time and at room temperature using GaN and Al target. Then, the films were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), and surface profiler to study their properties. XRD shows the GaN (101) and (013) plane for the AlGaN deposited at RF power of 30 W. Also there only GaN (101) for the AlGaN with 50 W RF power. Yet, the 70 W RF power shows the amorphous structure of AlGaN. The roughness and the grain size of AlGaN film from AFM analysis showed the trend of decreasing and increasing respectively. The roughness of the AlGaN films with 30 W power was 0.82 nm, 0.85 nm for 50 W, and 0.46 nm for 70 W RF power. The grain size of the AlGaN films was 30.06 nm, 32.10 nm, and 37.65 nm for RF power of 30 W, 50 W, and 70 W respectively. The profilometer found that the thickness of the AlGaN films was decreasing with increasing of RF power. This paper can demonstrate a successful co-sputtering technique of AlGaN. Despite AlGaN crystal structure was not able to found out in the XRD analysis, the effect of RF power has been studied to give significant effects on AlGaN thin film deposition.

The effects of variation of sputtering pressure of AlN HiPIMS deposition on Si substrate to the structure and electrical properties were investigated through XRD, AFM and impedance spectroscopy method. The strong preferred 100-plane AlN was observed for all samples from XRD pattern. The AlN thin film thickness was observed decrease with the increase of sputtering pressure. AFM analysis shows the lowest surface roughness at 0.84 nm for 5 mTorr sputtering pressure. Impedance spectroscopy analysis of Al/100-plane AlN/Si MIS structure shows the electrical conductivity of AlN was directly proportional to the sputtering pressure and stable with temperature ranging from room temperature (299 K) to 353 K. Good dielectric stability was achieved at 3 mTorr sputtering pressure for all variation temperature and the dielectric constant calculated at average 3.5.

In this study, a polycrystalline AlN thin films with a dominant peak of (100) plane under the sputtering parameters of 150 W with 2 hours deposition time are investigated. The study analyzes the effect of different negative bias voltages applied to the substrate holder of the sputtering system. The crystal structure analyzed by x-ray diffraction (XRD) shows that the AlN films is a hexagonal wurtzite structure. Sputtering the AlN films with higher negative bias voltage does increase the nitrogen atomic percentage. It was noticed that the AlN films deposited without any bias voltage resulted in close to stoichiometric of Al and N. It is also observed that the surface roughness of the AlN thin films does not change much with the increases of negative bias voltage.

The following topics are dealt with: nanofabrication; nanosensors; scanning electron microscopy; biosensors; II-VI semiconductors; zinc compounds; fibre optic sensors; electrochemical electrodes; chemical sensors; molecular biophysics.