Platinum diffusion in InAlAs was investigated utilizing a Pt/Ti/Pt/Au gate contact on an In0.52Al0.48As/In0.53Ga0.47As/InP high-electron-mobility transistor (HEMT) structure. Capacitance-voltage measurements on large gate field-effect transistors and high-resolution cross-sectional transmission electron microscopy enabled the measurement of Pt diffusion depth with nanometer-scale accuracy. A continuous increase in Pt diffusion depth was observed at an annealing temperature of 250C with increasing time. After a 40 min anneal, a diffusion depth of 8nm was measured. Such a deep Pt diffusion in a HEMT structure not only changes device parameters but also constitutes a serious reliability problem during device operation.

Measurements of Thermally-Induced Nanometer-Scale Diffusion Depth of Pt/Ti/Pt/Au Gate Metallization on InAlAs/InGaAs High-Electron-Mobility Transistors. S.Kim, I.Adesida, H.Hwang: Applied Physics Letters, 2005, 87[23], 232102 (3pp)