使用有機化學氣相沉積系統以介面差排陣列磊晶成長三五族銻化物材料對互補式金屬氧化物半導體之應用 = MOCVD GROWTH OF ANTIMONIDE

As downsizing of Si complementary metal oxide semiconductor (CMOS) devices comes to a standstill, III-V compound semiconductor has been attracting extensively as a promising alternating material for realizing ultra-high speed and low power consumption transistors. Among III-V materials, the integration of InxGa1-xSb materials on GaAs or Si substrate has been considered as the next generation of CMOS devices due to its high carrier mobilities, very low effective mass, controllable band gap and band engineering as combining with other III-V materials. However, due to the large lattice mismatch (>8%), anti-phase domains, and thermal expansion coefficient mismatch, the material has to relieve strain energy through misfit dislocations, threading dislocations, and other defects. Specially, these threading dislocations often propagate vertically to channel regions of devices, contributing to non-radiative recombination and degrading device performance. Therefore, highly lattice-mismatched of InGaSb-based epitaxial layers grown on GaAs or Si substrates for CMOS application have attracted significantly attention.

The majority issues of this dissertation focused on the growth of high quality InxGa1-xSb epitaxial layers on GaAs substrates under the interfacial misfit dislocation (IMF) growth mode by metalorganic chemical vapor deposition (MOCVD) method. By adjusting the growth conditions in a very narrow window, an IMF array is introduced and self-assembled at the epilayer/substrate interface to relieve the high lattice strain energy between the epilayer and substrate immediately. Thus, the epilayer can be achieved with very low defect density. It was found that the growth temperature is the main factor affecting the formation of the IMF array and the crystalline quality of the epilayer. The indium content and crystal quality of the InGaSb epilayer were enhanced by using a thin IMF GaSb buffer layer. In particular, the InxGa1-xSb (x < 0.3) epilayers showed very high quality with an rms roughness of <1.0 nm and the threading dislocation density of <9.0 × 106 cm-2.

The band offset parameters of Al2O3 high-k dielectric and InGaSb epilayer via two heterostructures (In0.15Ga0.85Sb/GaSb/GaAs and In0.28Ga0.72Sb/AlSb/GaSb/GaAs) was investigated. The results showed that both valence band offset (VBO) and conduction band offset (CBO) value of the InxGa1-xSb (x < 0.3) epilayer and Al2O3 were larger than 2.9 eV. Thus, the integration of Al2O3/InxGa1-xSb (x < 0.3) is feasible for both n-type and p-type channel MOSFET application. These results are an important contribution for the trend of InGaSb-based single channel CMOS devices. Moreover, the type-I straddling gap of both AlSb/In0.28Ga0.72Sb and AlSb/GaSb heterojunction with the VBO as well CBO values higher than 0.4 eV indicated in this study makes AlSb material as a potential barrier layer to prevent both of electron and hole back leakage currents in MOS devices.