Synchrotron X-ray topographic analysis of the impact of processing steps on the fabrication of AlGaAs/InGaAs p-HEMT's
McNally, Patrick J.ORCID: 0000-0003-2798-5121, Tuomi, Tiinamaija, Herbert, P.A.F., Baric, Adrijan, Äyräs, P., Karilahti, M., Lipsanen, H. and Tromby, M.
(1996)
Synchrotron X-ray topographic analysis of the impact of processing steps on the fabrication of AlGaAs/InGaAs p-HEMT's.
IEEE Transactions on Electron Devices, 43
(7).
pp. 1085-1091.
ISSN 1085-1091
Synchrotron X-Ray Topography (SXRT) has been uniquely applied to nondestructively reveal and evaluate the damage throughout the depth of the wafer, caused by the deposition of source/gate/drain metallization and of so-called “passivation” dielectric layers on power Al ₀.₂₂Ga₀.₇₈As/In₀.₂₁Ga₀.₇₉As pseudomorphic HEMT's. Device metallization is visible due to the stress imposed on the underlying substrate and is detected as a strain field by SXRT. Experimental results are in good agreement with simulation. The quality and detail of the initial control topographs disappear when the Si₃N₄ dielectric layer is deposited. This is believed due to the passivating layer introducing such strain into the crystal that it overwhelms the metallization strain, in addition to producing a significant amount of stress-induced defect and dislocation generation