Current Progress in Epitaxial Layer Transfer (ELTRAN(R))

Kiyofumi SAKAGUCHI  Nobuhiko SATO  Kenji YAMAGATA  Tadashi ATOJI  Yasutomo FUJIYAMA  Jun NAKAYAMA  Takao YONEHARA  

IEICE TRANSACTIONS on Electronics   Vol.E80-C   No.3   pp.378-387
Publication Date: 1997/03/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: INVITED PAPER (Special Issue on SOI Devices and Their Process Technologies)
Category: Wafer Technologies
porous,  BESOI,  pre-injection,  structure-sensitive etching,  hydrogen annealing,  edge exclusion,  batch process,  

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The quality of ELTRAN wafers has been improved by pre-injection in epitaxial growth, surface treatment just before bonding, high temperature annealing at bonding, high selective etching and hydrogen annealing. The pre-injection reduces defects. The surface treatment eliminates edge-voids. The high temperature bonding dramatically reduces voids all over the wafer. Hydrogen annealing is very effective for surface flattening and boron out-diffusion. In particular, the edge-void elimination by the surface treatment just before bonding is greatly effective for enlarging the SOI area and reduces the edge exclusion down to only two mm. The gate oxide integrity is well evaluated. This process promises high yield and through-put, because each of the steps can be independently optimized.