50 nm GaAs mHEMTs and MMICs for ultra-low power distributed sensor network applications

We report well-scaled 50 nm GaAs metamorphic HEMTs (mHEMTs) with DC power consumption in the range 1-150 ΜW/Μ demonstrating f<sub>T</sub> of 30-400 GHz. These metrics enable the realisation of ultra-low power (<500 ΜW) radio transceivers for autonomous distributed sensor network applications

Very high performance 50 nm T-gate III-V HEMTs enabled by robust nanofabrication technologies

In this paper, we review a range of nanofabrication techniques which enable the realization of uniform, high yield, high performance 50 nm T-gate III-V high electron mobility transistors (HEMTs). These technologies have been applied in the fabrication of a range of lattice matched and pseudomorphic InP HEMTs and GaAs metamorphic HEMTs with functional yields in excess of 95%, threshold voltage uniformity of 5 mV, DC transconductance of up to 1600 mS/mm and f/sub T/ of up to 480 GHz. These technologies and device demonstrators are key to enabling a wide range of millimeter-wave imaging and sensing applications beyond 100 GHz, particularly where array-based multi-channel solutions are required

Sub-micron, Metal Gate, High-к Dielectric, Implant-free, Enhancement-mode III-V MOSFETs

The performance of 300nm, 500nm and 1μm metal gate, implant free, enhancement mode III-V MOSFETs are reported. Devices are realised using a 10nm MBE grown Ga2O3/(GaxGd1-x)2O3 high-κ (κ=20) dielectric stack grown upon a δ-doped AlGaAs/InGaAs/AlGaAs/GaAs heterostructure. Enhancement mode operation is maintained across the three reported gate lengths with a reduction in threshold voltage from 0.26 V to 0.08 V as the gate dimension is reduced from 1 μm to 300 nm. An increase in transconductance is also observed with reduced gate dimension. Maximum drain current of 420 μA/μm and extrinsic transconductance of 400 µS/µm are obtained from these devices. Gate leakage current of less than 100pA and subthreshold slope of 90 mV/decade were obtained for all gate lengths. These are believed to be the highest performance submicron enhancement mode III-V MOSFETs reported to date

The Perioperative Nursing Workforce Program in NSW: How a professional perioperative nursing association meets one of its mandates Part 1

The need to review and change the way nursing care is delivered in perioperative settings is predicated on nursing workforce shortages, the changing, increasingly technologised and risk-prone OR practice milieu, and increasing demand for surgery. In responding to members' concerns about these issues, the NSW Operating Theatre Association Inc. (NSW OTA) in conjunction with and with sponsorship from the NSW Chief Nursing and Midwifery Officer, initiated and oversaw the development of a program, called the Perioperative Nursing Workforce Program (PNWP). The aims of this program are to make better use of human resources, to improve the way care is provided and thus improve patient outcomes; and to empower perioperative nurses so they are capable of independently improving their working environment. The program, which takes a practice development approach, program participants and some of their projects are presented in this paper. What is known about the topic The role of perioperative professional nursing associations is to write standards for practice and to assist in the professional development of their members. Practice development is hypothesised to assist clinical nurses to 'see' their work contexts afresh and to implement changes to improve patient care by focusing on patient-centredness and the use of credible evidence. What this article contributes It describes the contents and the implementation of a perioperative nursing workforce program, initiated by the NSW OTA and auspiced by the Chief Nursing and Midwifery Officer, NSW Health. The PNWP uses the tenets of practice development (PD) to achieve its aims and this is possibly the first use of PD in perioperative settings, and on a statewide basis

Sequential Sparse NMF

Nonnegative Matrix Factorization (NMF) is a standard tool for data analysis. An important variant is the Sparse NMF problem. A natural measure of sparsity is the L₀ norm, however its optimization is NP-hard. Here, we consider a sparsity measure linear in the ratio of the L₁ and L₂ norms, and propose an efficient algorithm to handle the norm constraints which arise when optimizing this measure. Although algorithms for solving these are available, they are typically inefficient. We present experimental evidence that our new algorithm performs an order of magnitude faster compared to the previous state-of-the-art

Sequential Sparse NMF

Nonnegative Matrix Factorization (NMF) is a standard tool for data analysis. An important variant is the Sparse NMF problem. A natural measure of sparsity is the L₀ norm, however its optimization is NP-hard. Here, we consider a sparsity measure linear in the ratio of the L₁ and L₂ norms, and propose an efficient algorithm to handle the norm constraints which arise when optimizing this measure. Although algorithms for solving these are available, they are typically inefficient. We present experimental evidence that our new algorithm performs an order of magnitude faster compared to the previous state-of-the-art

Determining the electronic performance limitations in top-down fabricated Si nanowires with mean widths down to 4 nm

Silicon nanowires have been patterned with mean widths down to 4 nm using top-down lithography and dry etching. Performance-limiting scattering processes have been measured directly which provide new insight into the electronic conduction mechanisms within the nanowires. Results demonstrate a transition from 3-dimensional (3D) to 2D and then 1D as the nanowire mean widths are reduced from 12 to 4 nm. The importance of high quality surface passivation is demonstrated by a lack of significant donor deactivation, resulting in neutral impurity scattering ultimately limiting the electronic performance. The results indicate the important parameters requiring optimization when fabricating nanowires with atomic dimensions

Enhancement Mode n-MOSFET with High-κ Dielectric on GaAs Substrate

In this paper, we report MOS heterostructures grown by molecular beam epitaxy on III-V substrates, employing a high-κ dielectric stack comprised of gallium oxide and gadolinium gallium oxide. Mobilities exceeding 12,000 and 6,000 cm2/Vs, for sheet carrier concentration ns of about 2.5x1012 cm-2 were measured on MOSFET structures on InP and GaAs substrates, respectively. These structures were designed for enhancement mode operation and include a 10 nm thick strained InGa1-xAs channel layer with In mole fraction x of 0.3 and 0.75 on GaAs and InP substrates, respectively

Resolution of Joint Molecules by RuvABC and RecG Following Cleavage of the Escherichia coli Chromosome by EcoKI

DNA double-strand breaks can be repaired by homologous recombination involving the formation and resolution of Holliday junctions. In Escherichia coli, the RuvABC resolvasome and the RecG branch-migration enzyme have been proposed to act in alternative pathways for the resolution of Holliday junctions. Here, we have studied the requirements for RuvABC and RecG in DNA double-strand break repair after cleavage of the E. coli chromosome by the EcoKI restriction enzyme. We show an asymmetry in the ability of RuvABC and RecG to deal with joint molecules in vivo. We detect linear DNA products compatible with the cleavage-ligation of Holliday junctions by the RuvABC pathway but not by the RecG pathway. Nevertheless we show that the XerCD-mediated pathway of chromosome dimer resolution is required for survival regardless of whether the RuvABC or the RecG pathway is active, suggesting that crossing-over is a common outcome irrespective of the pathway utilised. This poses a problem. How can cells resolve joint molecules, such as Holliday junctions, to generate crossover products without cleavage-ligation? We suggest that the mechanism of bacterial DNA replication provides an answer to this question and that RecG can facilitate replication through Holliday junctions