| AVS 61st International Symposium & Exhibition | |
| Materials Characterization in the Semiconductor Industry Focus Topic | Monday Sessions |
| Session MC+2D+AP+AS-MoA |
| Session: | Characterization of III-Vs (2:00-3:20 pm)/Photovoltaics, EUV masks, etc. (3:40-4:40 pm) |
| Presenter: | Marinus Hopstaken, IBM T.J. Watson Research Center |
| Authors: | M.J.P. Hopstaken, IBM T.J. Watson Research Center M.S. Schamis, IBM T.J. Watson Research Center Y. Sun, IBM T.J. Watson Research Center A. Majumdar, IBM T.J. Watson Research Center C.-W. Cheng, IBM T.J. Watson Research Center B.A. Wacaser, IBM T.J. Watson Research Center G. Cohen, IBM T.J. Watson Research Center K.K. Chan, IBM T.J. Watson Research Center D.K. Sadana, IBM T.J. Watson Research Center D.-G. Park, IBM T.J. Watson Research Center E. Leobandung, IBM T.J. Watson Research Center |
| Correspondent: | Click to Email |
Recently, there has been renewed technological interest for application of InGaAs and related III-V high-mobility materials as a potential replacement for the MOSFET Si-channel [1]. Successful integration of novel materials and processes requires accurate physical characterization of in-depth chemical distribution with nm-scale resolution. We will address some of the challenges regarding SIMS depth profiling of III-V materials and propose analytical solutions for the characterization of more complex multilayer substrates, impurities therein, and Ultra-Shallow Junction (USJ) doping profiles.
Ion beam based sputtering of III-V compounds is intrinsically more complex than in conventional Si substrates. One of the major issues with depth profiling of III-V materials is their higher sensitivity to formation of ion-beam induced topography, which has a detrimental impact on depth resolution [2]. We have previously reported anomalous sputtering behavior of (In)GaAs under low energy O2+ sputtering, causing severe degradation of depth resolution [3].
In case of low energy Cs+ sputtering at oblique incidence, we have achieved uniform sputtering conditions on different III-V compounds with no significant topography formation. We have demonstrated constant depth resolution in III-V multilayer structures with decay lengths as low as 2 nm/decade at low Cs+ impact energy (down to 250 eV).
We will address some of the analytical challenges regarding the quantification of depth and concentration scales in III-V multilayer structures, grown by hetero-epitaxy. We employ explicit corrections for yield variations using appropriate standards in their respective matrices. A special case occurs for the group IV n-type dopants (i.e. Si, Ge), which are typically monitored as negative cluster ion attached to the group V element for reasons of sensitivity. We have developed a quantification scheme to determine [Si] doping profiles in hetero-epitaxial structures, composed from the negative cluster ions (e.g. SiAs-, SiP-) in the respective matrices.
In summary, this work has improved our fundamental understanding of low-energy ion beam interactions in III-V materials, which is essential for achieving sub-nm depth resolution in thin-film structures. In addition, this work has provided with an optimum window of analytical conditions for quantitative analysis of a wide variety of impurities and dopants with high sensitivity in different III-V materials.
1. Y. Sun et al., IEDM 2013 Conf. Proc., p. 48-51.
2. E.-H. Cirlin, J. J. Vajo, R. E. Doty, and T. C. Hasenberg, J. Vac. Sci. Technol. A9, 1395 (1991).
3. M. J. P. Hopstaken et al., J. Vac. Sci. Technol. B28,1287, (2012).