The purpose of MONOFAST was to advance the state of the art in the design and fabrication of Monolithic Microwave Integrated Circuits (MMICs) towards higher operating frequencies.
The purpose of MONOFAST is to advance the state of the art in the design and fabrication of monolithic microwave integrated circuits (MMIC) towards higher operating frequencies.
The aim of the MONOFAST project is to develop a yield driven processing technology which will enable the design and construction of low noise amplifiers operating at 44 GHz. Both active and passive components are critical for the operation of these types of millimetre wave circuits, which will be based on coplanar waveguide (CPW) construction. As little is known about the design of CPW circuits, part of the work programme is concerned with the development of design methodologies for this interconnect technology.
Process and component design are being iteratively refined using reverse device engineering to converge towards a process technology capable of giving an acceptable yield in any future exploitation of the research field effect transistors (FET) with 0.2 micron T gates exhibiting performances close to the state of the art have been realised. The experimental and theoretical results already obtained concerning the coplanar passive waveguide elements are very interesting.
The technologies and components needed to obtain high performance and worthwhile yields from monolithic circuits working at the frequencies proposed lie at or beyond the present state of the art for two reasons. Firstly, the fabrication tolerances needed to contain device performance spreads within acceptable limits are severe, and are unattainable or exceptionally difficult to achieve using conventional integration processes. Secondly, circuit architectures must change: in particular, it is desirable to design around coplanar waveguide interconnections to minimise parasitic inductances and to allow dimensional flexibility whilst preserving characteristic impedance. The aim of the MONOFAST project was to develop a yield-driven processing technology to enable the design and construction of low-noise amplifiers operating at 44 GHz. Both active and passive components are critical for the operation of these types of millimetre-wave circuits, which were based on coplanar waveguide (CPW) construction.
As little was known about the design of CPW circuits, part of the work-programme was concerned with the development of design methodologies for this interconnect technology. The active devices were choosen to be T-gate MESFETs fabricated on material grown by MBE, although the technologies developed were intended to be readily applicable to HEMTs. High-resolution electron-beam and ion-beam lithographic methods were planned to be employed for pattern delineation, and dry etching was to be developed for forming recesses and to meet other etching needs. Most of the planned results have been achieved.
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CB4 4WS Cambridge
CB3 0ES Cambridge