Fabrication of GaAs Devices

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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Instrumentation for Research on Ultra-Small GaAs Devices.

10.21236/ada173246 ◽

1986 ◽

Author(s):

James S. Harris

Keyword(s):

Gaas Devices

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Ohmic contacts for GaAs devices using epitaxial Ge films

10.1109/iedm.1977.189202 ◽

1977 ◽

Author(s):

W.T. Anderson ◽

A. Christou ◽

J.E. Davey

Keyword(s):

Ohmic Contacts ◽

Gaas Devices

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Monolithic Integration of Si and GaAs Devices

MRS Proceedings ◽

10.1557/proc-67-165 ◽

1986 ◽

Vol 67 ◽

Cited By ~ 5

Author(s):

H. K. Choi ◽

G. W. Turner ◽

B-Y. Tsaur ◽

T. H. Windhorn

Keyword(s):

Monolithic Integration ◽

Double Heterostructure ◽

Si Substrates ◽

Gaas Substrates ◽

Gaas Devices ◽

Voltage Pulses ◽

First Time

ABSTRACTIntegration of Si MOSFETs with GaAs MESFETs and with GaAs/AlGaAs double-heterostructure LEDs on monolithic GaAs/Si substrates is reported. Both Si MOSFETs and GaAs MESFETs show characteristics comparable to those for devices fabricated on separate Si and GaAs substrates. In LED/MOSFET integration, the cathode of each LED is connected with the drain of a MOSFET. This is the first time that Si and GaAs devices have been monolithically interconnected. LED modulation rates up to 27 Mbps have been achieved by applying a stream of voltage pulses to the MOSFET gate.

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