Micro-photoluminescence imaging of dislocation generation in 0.18μm power semiconductor devices with deep trenches

(Invited) Impact of the Substrate Specifications on the Extended Defects Induced by the Deep Trench Isolation

“…The Micro-Photoluminescence Imaging (µ-PLI) uses excitation of charge carriers in silicon using high intensity illumination, followed by observation at longer wavelength of photons generated from radiative recombination at defect sites in silicon and selected by the means of band-pass filters. In the previous works (3,11), µ-PLI was used to study the implantation defects and the dislocation formation generated by the DTI. In this work the µ-PLI extracts the DZ, through a depth scan of the photoluminescence signal coming from the BMD registering the depth at which the BMD density starts to increase.…”

“…However, the DTI induces a certain crystal defectivity because of the mechanical stress generated during the thermal processes. The stress in silicon is associated with the mismatch in coefficient of thermal expansion between silicon (2.5 ppm/˚C) and silicon dioxide (0.5 ppm/˚C), the volume expansion associated with thermal oxidation, and the volume shrinkage associated with grain growth in the polysilicon (3). The investigation of stress distribution around trench isolation using two-dimensional finite element simulation and the micro-Raman technique confirmed that the stress value reaches a local maximum at the bottom of the trench structure, and this stress can be sufficiently high to generate crystal defects already for trenches of few microns (4).…”