첨부된 STREEM AlGaN 소개 자료와 아래 핵심 시뮬레이션 기능에 대한 요약 참고하십시오
STREEM-AlGaN is a specialized software tool for self-consistent modeling
of the evolution of stress and bow, as well as dislocation dynamics
during the growth and cooling (0001) III-Nitride heterostructures by
MOCVD on silicon and sapphire wafers. Within the software, it is
possible to both analyze the stress in the structure at different stages
of the growth, using the processing of in-situ curvature data (inverse
problem solution), and predict stress, bow, and dislocation density in
the whole structure or particular layers, using the growth conditions as
the input parameters (direct problem solution).
To find process parameters, allowing crack-free growth, a criterion of
cracking during the growth and cooling is implemented into the software.
The software is aimed at understanding and control of the structure
properties by adjusting the process recipe. In particular, the following
issues can be addressed:
- evolution of curvature at the stages of heating, growth, and cooling
of the structure under various process parameters and sequences of the
layers, forming the heterostructure;
- stress relaxation in compressively stressed layers;
- dislocation dynamics, including nucleation, inclination, and
annihilation of threading dislocations;
- crack formation induced by tensile stress both during the growth and
cooling of the structure;
- influence of the process parameters on the through-wafer temperature
drop and its contribution to the structure bow;
- stress state in the particular layers via processing of in-situ
curvature data and use of the extracted stress distribution as the
initial stage to simulate curvature evolution for a more complex structure.
As a result of the modeling, the user can analyze such characteristics
as the stress, curvature, bow, effective lattice parameter, and
temperature gradient across the wafer as well as the density and
inclination angle of threading dislocations across the heterostructure.
By adjusting the recipe parameters, including the temperature, thickness
and composition of the layers, sequence and durations of the particular
stages of the process, the user can follow the respective changes in the
above characteristics and establish correlations between the recipe and
properties of the heterostructure.
