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GaAs electronic devices are becoming increasingly used in the microelectronics industry especially in solid state microwave, ultra high speed digital processing and optoelectronic applications. However, in the manufacture of the GaAs devices, problems due to the inherent brittleness of the GaAs and batch to batch variability of the bond pad metallisation have commonly been experienced. This has resulted in some difficulties in wire bonding to GaAs devices with ultrasonic and thermocompression wire bonding techniques. This paper describes a programme undertaken to investigate Au wire bonding techniques to GaAs devices. Specifically, bonding trials have been performed on a range of GaAs substrates using pulse tip and continuously heated thermocompression bonding and ultrasonic bonding. The results of this work have shown that thermocompression and ultrasonic wire bonding techniques are cabable of producing acceptable bonds to GaAs devices, although some of the advantages and limitations of each technique have been demonstrated. Thermocompression bonding with a continuously heated capillary gave the most tolerant envelope of bonding conditions and highest bond strengths. Pulse tip thermocompression bonding gave a less tolerant envelope of acceptable bonding conditions, required a longer bonding time and the wire was weakened above the ball bond. Ultrasonic bonding did not require any substrate heating to give acceptable bonds. However, the choice of equipment can be critical if damage to the device is to be avoided.

The purpose of this paper is to examine an ongoing process of logic assimilation within an amateur sports organisation (ASO) called the Gaelic Athletic Association (GAA). It seeks to develop our understanding of how forms of accounting mitigated (or exacerbated) the tensions that arose among GAA members due to the consequences of the assimilation of select elements of a professional logic and a commercial logic within its traditionally dominant social welfare logic.

Interviews were undertaken with representatives and members of the GAA to understand the effects of growing commercialisation and professionalisation on the organisation’s traditional amateur status and social mission. In particular, the authors sought to understand how accounting, in the form of financial reporting, influenced the extent of the tensions that arose. Interviews were supported by an extensive collection of podcasts and news articles that discussed this topic.

The paper’s findings offer unique empirical insights into the role played by forms of accounting in the maintenance of amateurism within an ASO. It reveals the conflicting role of financial reporting within the GAA whereby it was used by the GAA’s management to ease member concerns surrounding logic assimilation while simultaneously being ignored by clubs and counties to facilitate payments to managers thereby eroding the amateur status of Gaelic Games.

The paper is unique in its exploration of logic assimilation within a form of hybrid organisation that has previously been unexamined in the accounting literature. It extends extant understandings of how accounting influences the co-existence of potentially conflicting logics. The paper also discusses the implications of what accounting makes visible and keeps invisible on the longevity of the traditionally dominant social welfare logic within an ASO.

The purpose of this paper is to present global airline alliances from a complementary and original angle to the existing works: “specific social networks”. “Social” as it is an inter‐organisational network through business relations between airline companies and “specific” as these are formal relations of contractual types (joint marketing, code sharing agreements, etc.).

It is an empirical study, about cooperation agreements between global regular airlines, over a time period of six years from Airline Business Review database. The graph theory is used to measure social network and graphics representation for illustrations.

The results show that there is a real process of social embeddedness correlated to the airline alliances members' experiences. Their structuring as networks varies in time following a life cycle and their specific morphologies affect their performance.

The paper proposes numerous measures to approach the structure of airline alliances and graphics representations to illustrate networks.

The paper draws a synthesis from the morphology and morphogenesis of airline alliances, proposing thereby some of their structural properties which have an impact on their competitiveness.

Recent developments in microwave GaAs technology are yielding devices with higher power capabilities and increased levels of integration. The mechanical and thermal properties of GaAs and other microwave materials play a key role in the design and assembly of microwave power circuits. Thermal management is a critical element of microwave power circuit design. Thermal properties of microwave materials are discussed and compared with standard microelectronic materials. Material selection criteria are described. Assembly and packaging techniques also affect the overall performance of the GaAs power circuit. The high operating frequencies of microwave circuits make ordinary circuit elements, such as wire bonds and printed conductors, reactive. In addition, electrical performance criteria, such as high current or low impedance, create unique assembly demands. The successful development of a GaAs‐based microwave product is dependent on careful attention to the material properties and precise assembly methods. Techniques of automated assembly and processing are discussed, with ah eye towards maintaining high quality and reliability.

An empirical velocity‐field relationship, based on Monte Carlo simulation, is used to modify a drift‐diffusion model for the characterization of short gate GaAs MESFET's. The modified drift‐diffusion model is used to generate both the steady‐state and the small‐signal parameters of submicron GaAs MESFET's. The current, transconductance, and cutoff frequency are compared with two‐dimensional Monte Carlo simulation results on a 0.2 µm gate‐length. The model is also used to predict measured I‐V and s‐parameters of a 0.5 µm gate‐length ion‐implanted GaAs MESFET. The comparison and the analysis made, support the accuracy of the modified drift‐diffusion simulator and makes it computationally efficient for analysis of short‐gate devices.

This paper aims to improve the device performance from the perspective of reducing ohmic contact resistance; the effects of different electrode structures and alloying parameters on the series resistance and power-current-voltage of laser diodes (LDs) have been investigated in this paper.

Four groups of p-GaAs side metal electrodes with different metal layer arrangements and thicknesses are fabricated for the investigated LDs. The investigated p-GaAs side electrodes are based on Ti/Pt/Au material and the n-GaAs side metal electrodes all have a same structure of Ni/Ge/Ni/Au/Ti/Pt/Au. The LDs with different electrodes were alloyed at 380°C for 60 s and 420°C for 80 s.

The experimental results show that the series resistance decreases by 14%–20%, the output power increases by 2%–2.2% and the conversion efficiency increases by 1.69%–2.16% for the LDs prepared with optimized alloying parameters (420°C for 80 s). The laser diode with p-GaAs side Ti/Pt/Au electrode of 30/70/100 nm has the best device characteristics under both annealing conditions.

The utilization of this improvement on ohmic contact property in electrode is not only very important for upgrading high-power LDs but also helpful for GaAs-based microelectronic devices such as HBT and monolithic microwave integrated circuit.

A transport model has been developed which is reasonably accurate, and has proven quite efficient for the two‐dimensional numerical simulation of submicron‐scale Si and GaAs devices. In this model an approximate form of the energy‐transport equation is developed; this equation is easily included in otherwise‐conventional device simulation codes, which then require only slightly more solution time than standard models using field‐dependent transport coefficients. Calculations for 0.25 micron gate length Si and GaAs MESFET's show that velocity overshoot effects can be very important, particularly in the latter material; predicted saturation currents in the GaAs devices are almost three times larger than those that would have been predicted using conventional transport models. The model described, and its application in simulation programs, should find use in the design of submicron‐scale devices to properly take advantage of overshoot phenomena.

Examines the influence of various audit firm and client characteristics on compliance with Generally Accepted Auditing Standards’ (GAAS) reporting standards for private sector audits performed by small audit firms. Because prior studies in this area have focused on public sector audits, an important contribution of this study is the use of an observable quality measure as the dependent variable on audits performed in the private sector. Obtains data for the study from the quality reviews of firms licensed to practise in the State of Arkansas during the years 1989‐1991. Suggests that audit fees, the complexity of the engagement and membership in the state Certified Public Accountants’ society are positively related to compliance with GAAS reporting standards on private sector engagements performed by small audit firms. In addition, firm size is negatively related to compliance with GAAS reporting standards on private sector engagements performed by small audit firms.

A compound emitter heterojunction bipolar transistor (HBT) structure that incorporates an additional heterojunction within the emitter for minority carrier confinement has been proposed. In this new device configuration, the single wide band‐gap emitter layer in a conventional HBT is replaced by two sub‐layers of wide band‐gap material, with the sub‐layer nearer the base having a narrower band‐gap. By means of numerical simulations, the compound emitter HBT was found to perform better than comparable conventional HBTs. With the AlGaAs(n) / GaAs heterostructure system, the optimum compound emitter HBT structure was found to be Al0.3Ga0.7As(n) ‐ Al0. 2Ga0.8As(n) / GaAs with grading at the two hetero‐interfaces. It has a low turn‐on voltage that is almost identical to that of a homojunction GaAs bipolar transistor with similar doping conditions. Compared with a conventional single emitter layer Al0.3Ga0.7As/GaAs HBT, the optimum compound emitter HBT has an enhancement in the current gain by approximately 2 folds, an improvement in the uniform current gain region from 2 to 4 decades of collector current density, and a slight increase in the unity‐gain cut‐off frequency fT by about 7 %.

A material that could well replace the silicon chip in future generations of aircraft communications, radar and early warning systems, is now under active development in various military and industrial establishments. Speed is the essence in any communication system and it has been determined that electrons will move six times faster through gallium arsenide (GaAs) than through silicon. GaAs substrates also have the important characteristic of having high resistivity. The superiority of silicon over gallium arsenide at the present time is principally due to the considerable developments that have taken place over many years in Silicon Valley, California, and other research centres. This has resulted in GaAs integrated circuits supporting only several hundred components compared with the near 500,000 in silicon (si).