Electron Beam/Optical Hybrid Lithography For The Production Of Gallium Arsenide Monolithic Microwave Integrated Circuits (Mimics)

1988 ◽  
Author(s):  
Rao M. Nagarajan ◽  
Steven D. Rask
1987 ◽  
Vol 65 (8) ◽  
pp. 885-891
Author(s):  
S. Dindo ◽  
R. North ◽  
D. Madge

Over the last several years, Optotek has successfully developed the capability to design and process high-frequency x-band monolithic microwave integrated circuits. A process for fabricating active devices and passive elements is described. In addition, dc and microwave measurements are presented.


1985 ◽  
Vol 63 (6) ◽  
pp. 736-739
Author(s):  
M. Gaudreault ◽  
M. G. Stubbs

Gallium-arsenide monolithic microwave integrated circuits (GaAs MMIC's) promise the microwave circuit designer significant size, weight, and reliability advantages. Distributed and lumped matching techniques have been utilized previously in MMIC design with the latter offering greater bandwidth and smaller size. In this paper, experimental results for lumped interdigitated capacitors on a gallium-arsenide substrate are presented. Computer modelling in the frequency range 2–18 GHz was used to derive a set of design curves for these capacitors. These curves cover aspect ratios of w/s = 1 and w/s = 2.5. Experimental results obtained by using these curves to design lumped-element monolithic filters show excellent agreement with theory.


Author(s):  
Richard G. Sartore

In the evaluation of GaAs devices from the MMIC (Monolithic Microwave Integrated Circuits) program for Army applications, there was a requirement to obtain accurate linewidth measurements on the nominal 0.5 micrometer gate lengths used to fabricate these devices. Preliminary measurements indicated a significant variation (typically 10 % to 30% but could be more) in the critical dimensional measurements of the gate length, gate to source distance and gate to drain distance. Passivation introduced a margin of error, which was removed by plasma etching. Additionally, the high aspect ratio (4-5) of the thick gold (Au) conductors also introduced measurement difficulties. The final measurements were performed after the thick gold conductor was removed and only the barrier metal remained, which was approximately 250 nanometer thick platinum on GaAs substrate. The thickness was measured using the penetration voltage method. Linescan of the secondary electron signal as it scans across the gate is shown in Figure 1.


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