Ž. Mozolová

The improved performance of GaAs micromachined power sensor microsystem

Thermal effects in a 2-μm thick GaAs cantilever beam of the power sensor microsystem are investigated. The increased thermal sensitivity of the microsystem to the thermal conductance changes of the ambient atmosphere is evaluated by the experiment and simulation. A bimetallic effect in the microsystem cantilever beam is studied using both the microscopic laser optical interferometry and laser optical reflectance measurement. The cantilever beam deflections induced by the differential thermal expansion of the cantilever layers are found to be linear with the power dissipated in the microsystem MESFET-heater. The key microsystem transfer characteristics based on the bimetallic effect are obtained.

The fabrication of thin GaAs cantilever beams for power sensor microsystem using RIE

A method of fabricating two independent thin GaAs cantilever beams using a bulk micromachining technology based on RIE has been developed. The principle of the method is outlined and results of a three-dimensional patterning of the cantilever beams successfully applied in a power sensor microsystem development are described.

T-shaped gates for heterostructure field effect transistors

Two different approaches for the HFETs T-shaped gate fabrication are presented. Besides the conventional approach based on the three-layer resist structure a new one based on the poly Si/polyimide bilayer is demonstrated using which a ratio of the gate head length to the gate foot length larger than 10 is achieved. Both of the fabrication techniques presented seem to be very promising for nanometer T-shaped gate formation in the recent various design concepts of HFETs for millimeter-wave band applications.