New Generation of BAW Technology has been developed. It supports the full frequency range from 1 GHz to above 8 GHz including the 5G NR and WiFi6E frequency bands. Furthermore, it provides significant improvements in resonator performance: up to 100% higher Q, over 50 % TCF improvement and improved modes behavior. It also makes Sc doping or higher Sc doping applicable to more frequency bands. Moreover, the resonator size could be decreased significantly at the same time. Thus, filters have better power handling, IL and rejection in pair with device shrinkage of up to 50 %.

As more LTE bands are squeezed into the crowded global RF spectrum interference becomes a major concern. Some cases require profoundly steep transitions from passband to the tightly packed neighboring bands. The most demanding high frequency LTE bands may only be served with high-performance BAW resonators that have been temperature compensated to have essentially zero temperature drift. There is a variety of known challenges associated with the traditional temperature compensation techniques applied to BAW devices. This work will address those challenges and present a novel no-drift BAW-SMR using over-moded acoustic reflector layers. A solution for Band 30 utilizing the over-moded reflector will be presented.

We present efforts and methods to model the thermal behavior of wafer level packaged (WLP) bulk acoustic wave (BAW) filters. Many key parameters of modern RF filters are temperature dependent. Excessive self-heating, especially in TX-path filters, can lead to severe performance degradation. Even more fatal, unrecoverable failure conditions can occur. Having supportive data early-on in the design phase of a filter is crucial. It saves expensive and time-consuming design iterations and thus gives margin for more efficient and reliable filter development. The presented simulation method offers the advantage of incorporating the effects of the module geometry into the thermal simulation. Not only the die layout is considered, but, for example, also the impact of different laminate variants can be studied. Additionally, it allows simulations to run with traditional circuit simulator speed for different stimuli i.e. CW-tones at different frequency positions.

This paper focuses around two key aspects around recent advances in Bulk Acoustic Wave technology. The first portion discusses the impressive strides taken in improved electrical filter and duplexer performance. The second part deals with a reduction of the application foot print by means of introducing a wafer-level packaging approach, allowing flip-chip mounting of the SMR-BAW die. This renders bond wires surrounding the BAW die obsolete, and thus reduces the overall real-estate required in and application significantly.

We report electronic transport investigations of mechanically templated carbon nanotube single electron transistors (SETs). The devices were fabricated on a Si/SiO2 substrate by controllably placing individual single walled carbon nanotubes (SWNTs) between the source and drain electrodes via dielectrophoresis with a 100 nm wide local Al/Al2O3 bottom gate in the middle. From the low temperature electronic transport measurements, we show that a quantum dot is formed whose charging energy can be tuned from 10 to 90 meV by varying both the local gate and Si backgate. The temperature dependent measurements show that the Coulomb oscillations persist up to 250 K. The transport properties can be explained by a simple potential configuration, which suggests that two tunnel barriers are formed due to the bending of the SWNT at the local gate edges and that the size of the dot and tunnel barrier transparency can be tuned by the gates allowing the operation of SET in a wide temperature range and thereby realizing a controllable and tunable SET. Our simple fabrication technique and its tunability over a large temperature range could facilitate large scale fabrication of SET for practical applications.

As wireless mobile applications continue to drive shrinkage of the individual components, consequently a corresponding decrease in required footprint and component thickness needs to go along with it. Over the last years, the size of power amplifier duplexer (PAD) front-end modules as well as standalone duplexers has steadily decreased. A significant portion of this shrinkage has been contributed by a decrease in BAW die size. This decrease is driven by various technology improvements. In this paper we will first discuss the introduction of on-chip capacitors. These capacitors not only allow for a reduction of the required external component count, but also for an increased degree of design freedom. Second, we will discuss how the shrinkage of reflector metal dimensions leads as a direct result to an significant reduction in die sizes. Although core technology improvements can allow for radical BAW die shrinkage, the packaging technology that comes along with the BAW die needs to contribute its share to maintain this trend. Last, a novel approach for wafer-level packaging BAW die will be presented.

We report ultrahigh density assembly of aligned single-walled carbon nanotube (SWNT) two-dimensional arrays via AC dielectrophoresis using high-quality surfactant-free and stable SWNT solutions. After optimization of frequency and trapping time, we can reproducibly control the linear density of the SWNT between prefabricated electrodes from 0.5 SWNT/μm to more than 30 SWNT/μm by tuning the concentration of the nanotubes in the solution. Our maximum density of 30 SWNT/μm is the highest for aligned arrays via any solution processing technique reported so far. Further increase of SWNT concentration results in a dense array with multiple layers. We discuss how the orientation and density of the nanotubes vary with concentrations and channel lengths. Electrical measurement data show that the densely packed aligned arrays have low sheet resistances. Selective removal of metallic SWNTs via controlled electrical breakdown produced field-effect transistors with high current on-off ratio. Ultrahigh density alignment reported here will have important implications in fabricating high-quality devices for digital and analog electronics.

We report on high quality individual solution processed single-walled carbon nanotube (SWNT) field effect transistors assembled from a commercial surfactant free solution via dielectrophoresis. The devices show field effect mobilities up to 1380 cm2/V s and on-state conductance up to 6 μS. The mobility values are an order of magnitude improvement over previous solution processed SWNT devices and close to the theoretical limit. These results demonstrate that high quality SWNT devices can be obtained from solution processing and will have significant impact in high yield fabrication of SWNT nanoelectronic devices.

We performed low-temperature electron transport spectroscopy to evaluate defects in individual single-walled carbon nanotube (SWNT) devices assembled via dielectrophoresis from a surfactant-free solution. At 4.2 K, the majority of the devices show periodic and well-defined Coulomb diamonds near zero gate voltage corresponding to transport through a single quantum dot, while at higher gate voltages, beating behavior is observed due to small potential fluctuations induced by the substrate. The Coulomb diamonds were further modeled using a single electron transistor simulator. Our study suggests that SWNTs derived from stable solutions in this work are free from hard defects and are relatively clean. Our observations have strong implications on the use of solution-processed SWNTs for future nanoelectronic device applications.

The authors demonstrate directed assembly of high quality solution processed single-walled carbon nanotube (SWNT) devices via ac dielectrophoresis using commercially available SWNT solutions. By controlling the shape of the electrodes, concentration of the solution, and assembly time, the authors are able to control the assembly of SWNTs from dense arrays down to individual SWNT devices. Electronic transport studies of individual SWNT devices show field effect mobilities of up to 1380 cm2/V s for semiconducting SWNTs and saturation currents of up to ∼15 μA for metallic SWNTs. The field effect mobilities are more than an order of magnitude improvement over previous solution processed individual SWNT devices and close to the theoretical limit. Field effect transistors (FET) fabricated from aligned two-dimensional arrays of SWNT show field effect mobility as high as 123 cm2/V s, which is three orders of magnitude higher than the solution processed organic FET devices. This study shows promise for commercially available SWNT solution for the parallel fabrication of high quality nanoelectronic devices.

We demonstrate solution processable large area field effect transistors (FETs) from aligned arrays of carbon nanotubes (CNTs). Commercially available, surfactant free CNTs suspended in aqueous solution were aligned between source and drain electrodes using ac dielectrophoresis technique. After removing the metallic nanotubes using electrical breakdown, the devices displayed p-type behavior with on-off ratios up to ∼2×104. The measured field effect mobilities are as high as 123 cm2/V s, which is three orders of magnitude higher than typical solution processed organic FET devices.

We investigated the mechanism for photoconduction in multi-walled carbon nanotube (MWNT) film of various electrode separations upon near infrared illumination. In addition to observing strong dependence of photocurrent on the position of the laser spot, we found that the time constant of the dynamic photoresponse is slow and increases with increasing electrode separations. The photoconduction mechanism can be explained by the Schottky barrier modulation at the metal-nanotube film interface and charge carrier diffusion through percolating MWNT networks.

We present a near IR photoresponse study of large area multiwalled carbon nanotube/poly(3-hexylthiophene)-block-polystyrene polymer (MWNT/P3HT-b-PS) nanocomposite films for different loading ratio of MWNT into the polymer matrix. We show that the photocurrent strongly depends on the position of the laser spot with maximum photocurrent occurring at the metal-film interface. In addition, compared to the pure MWNT film, the photoresponse is much larger in the MWNT/polymer composite films. The time constant for the photoresponse is slow and varies between 0.6 and 1.2 s. We explain the photoresponse by Schottky barrier modulation at the metal-film interface.

We report the fabrication and electron transport investigation of individual local-gated single-walled carbon nanotube field effect transistors (SWNT-FET) with high yield using a semiconducting-rich carbon nanotube solution. The individual semiconducting nanotubes were assembled at the selected position of the circuit via dielectrophoresis. Detailed electron transport investigations on 70 devices show that 99% display good FET behavior, with an average threshold voltage of 1 V, subthreshold swing as low as 140 mV/dec, and on/off current ratio as high as 8 × 105. The high yield directed assembly of local-gated SWNT-FET will facilitate large scale fabrication of CMOS (complementary metal–oxide–semiconductor) compatible nanoelectronic devices.