Gate Sinking Effect of 0. 1 /spl mu/m InP HEMT MMICs Using Pt/Ti/Pt/Au

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

“…RELIABILITY PERFRORMANCE Initial reliability performance was evaluated based on the exit criterion of delta S 21 ≤ -1 dB at 35 GHz with the assumption of the Ea of 1.5 eV based on the lifetesting results at T ambient of 280 °C. The Ea was validated to be greater than 1.5 eV for Pt-sunken gate InP HEMTs [12,33]. Moreover, our recent 3-temperature lifetest demonstrates that the Ea of Ptsunken gate InP HEMT MMICs on 4-inch InP substrates is greater than 1.5 eV [36].…”

“…Figure 4 depicts the gradual S 21 degradation of a Pt-sunken InP HEMT SEC subjected to lifetest at T ambient of 280 °C. The initial S 21 increase was found to be caused by the initial nominal Pt gate sinking effect [33]. The continuing lifetesting of Pt-sunken InP HEMT SECs after reaching ΔS 21 = -1 dB could cause more drastic S 21 degradation.…”

“…Although the reliability performance of Pt-sunken InP HEMT was reported based on the transconductance degradation, Δg m , of -10 % on discrete InP MHEMTs [12] and drain current degradation, ΔIdss, of -20 % on InP HEMT MMICs on 3-inch InP substrates [33], the reliability analysis using the ΔS 21 of -1 dB at 35 GHz for Pt-sunken InP HEMT MMICs on 4-inch InP substrates is still lacking. Also, the reliability analysis of r. f. performance represents the real scenario of InP HEMT LNAs during lifetime operation.…”

“…The Pt-sunken gate was initially introduced to fabricate high performance and enhancementmode InP HEMTs [31][32]. Although recent investigation shows that InP HEMTs with Pt-sunken gate have demonstrated superior reliability performance to InP HEMTs with Ti-gate [12,[25][26]33], the reliability evaluation of 0.1-μm Pt-sunken gate InP HEMT MMICs on 4-inch InP substrates has been lacking. The fabrication of 0.1-μm InP HEMT low noise amplifiers (LNAs) on 4-inch InP substrates is essential for next-generation high performance phased-array applications requiring a high volume of LNA elements [2].…”

Au electromigration and Ti segregation in TiPtAu gate of PHEMTs

“…The process for GaAs PHEMT is very ripe, but the stability of contaction of gate metal is still a bottleneck of reliability performance [1][2][3]. Because of the instability of contact with gate metal, the metal element will migrate into the inner of device while the semiconductor element (such as Ga in GaAs) will diffuse toward outside [4,5], which will lead to the decrease of the distance between the gate metal and the InGaAs channel layer and effect the typical DC and RF performance, such as the degradation of IDS, GM, and Pout. One of the main problems for the stability of contact of gate metal is that the metal atom will migrate toward one direction under the effects of thermal and electrical stresses.…”