Shadow mask selective area molecular beam epitaxy for applications in device processing and integration

This thesis describes the development of a shadow mask selective area molecular beam epitaxy (MBE) technique and its applications in device structure processing and integration.; Two kinds of mask fixtures were designed and fabricated to perform shadow mask selective area epitaxy (SAE) during molecular beam epitaxial growth. The ex situ mask fixture requires the mask to be placed and removed outside the growth environment during the mounting and removing of the substrate. The in situ mask fixture allows the mask to be placed and removed inside the vacuum chamber. Therefore patterned layer growth can be performed within the structure wherever desired and multiple step SAE can be performed for complex device structures. The growth behaviors of the shadow mask SAE employing these fixtures were investigated and presented.; The implementations of the shadow mask SAE technique on device structure processing and integration were demonstrated by the in situ processing of Au/CdTe detector-array-like structures for application in HgCdTe detector array fabrication, and by the integration of different ZnCdSe quantum wells on a single GaAs or InP substrate for application in integration of red-green-blue (Zn,Cd,Mg)Se based light emitting diodes on single InP substrate. The in situ mask fixture was used in these applications.; The influence of the shadow mask SAE on material quality was studied by investigating the defect density of the patterned CdTe and ZnSe layers grown with the shadow mask. Similar defect density was observed from these patterned epilayers as from the flat epilayers, indicating that no deleterious effect on the material quality was caused by the use of shadow mask. However, we were unable to identify if there is any defect reduction effect by the use of shadow mask SAE as there is with the patterned-substrate SAE due to the limited growth area.; A wide range of characterization techniques such as Photoluminescence (PL), micro-PL, X-Ray Diffraction (XRD), Secondary Ion Mass Spectroscopy (SIMS), Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) were used in this research work to characterize the materials and device structures fabricated.