Degradation mechanism and reliability improvement of InGaAs/InAlAs/InP HEMTs using new gate metal electrode technology

A review of InP/InAlAs/InGaAs based transistors for high frequency applications

“…Ultralow-noise InP HEMTs have been demonstrated and fabricated for cryogenic temperature operation [244][245][246][247][248][249][250][251]. .…”

Progressive Schottky junction reaction induced degradation in Pt-sunken gate InP HEMT MMICs for high reliability applications

“…Nevertheless, gate metal reaction with the InAlAs material in InP HEMTs subjected to elevated temperature lifetest was still observed to be the primary degradation mechanism. A recent investigation of InP HEMTs degradation using a scanning-transmission-electronmicroscope (STEM) technique [26] reveals the physical evidence of Ti-InAlAs reaction in InP HEMTs under the elevated temperature lifetest. Although the high activation energy (Ea) was reported in InP HEMTs with the gate metal stacks of Ti/Pt/Au [20,30], the degree of reaction between the gate metal stacks of Ti/Pt/Au and the InAlAs Schottky barrier layer strongly depends on the InAlAs surface conditions prior to the Ti/Pt/Au gate metal deposition.…”

“…Several degradation causes in InP HEMTs were reported in literature [16,[21][22][23][24][25][26][27][28][29][30], however, most of them were eliminated due to the maturity of manufacturing processes and HEMT epitaxial materials. Nevertheless, gate metal reaction with the InAlAs material in InP HEMTs subjected to elevated temperature lifetest was still observed to be the primary degradation mechanism.…”

“…Therefore, it is essential to mitigate the Ti-InAlAs reaction of InP HEMTs under elevated temperature lifetest to assure repeatable high reliability performance. To improve the reliability performance of InP HEMTs, new gate metal stacks were explored recently to reduce the TiInAlAs reaction [24][25][26]. The Pt-sunken gate was initially introduced to fabricate high performance and enhancementmode InP HEMTs [31][32].…”

“…The variations of reliability performance were mainly attributed to different degradation mechanisms, consisting of fluorine contamination [23], ohmic contact degradation [16], gate metal stacks [24][25][26], layer structure [27], bias dependence [28], the variation of gate recess depth [29][30], and gate metal sinking [21][22]. It was observed that the degradation mechanisms strongly depend on the process techniques employed in a particular InAlAs/InGaAs/InP HEMT technology, therefore causing the distinct reliability performance from company to company.…”