Impact of bonding temperature on the performance of In0.6Ga0.4As Metamorphic High Electron Mobility Transistor (mHEMT) device packaged using Flip-Chip-on-Board (FCOB) technology

In this study, we fabricated 150-nm In
_0.6
Ga
_0.4
As mHEMT devices using in-house fabrication process. The devices were packaged using FCOB technology on organic substrates. The packaged device exhibited favorable DC characteristics with I
_DS
= 350 mA/mm and a transconductance of 600 mS/mm at V
_DS
= 0.5V with a maximum available gain (MAG) 6.5 dB at 60 GHz. The impact of temperature setting during the bonding process on the DC and RF performance was experimentally investigated. RF performance degradation was observed at high bonding temperature due to the induced thermomechanical stress. The stress was mainly from the mismatch in the coefficient of thermal expansion (CTE) of the GaAs chip and organic substrate.