This chapter provides a comprehensive overview of the evolution, fabrication, characterization, and applications of silicon-on-insulator (SOI) wafers produced using the SIMOX (Separation by IMplanted OXygen) process. SIMOX technology, developed in the 1970s, involves high-dose O⁺ implantation into a silicon substrate followed by high-temperature annealing (>1300 °C) to form a buried silicon dioxide (BOX) layer. Modern advances, particularly the Modified Low-Dose (MLD) SIMOX process, enable precise control of both the BOX and SOI layer thicknesses, down to sub-500 Å for fully-depleted CMOS devices, with high structural and electrical integrity.
Key developments include high-temperature implantation (>500 °C), internal thermal oxidation (ITOX) to improve BOX continuity and electrical quality, and process standardization for high-volume integrated circuit (IC) production. MLD SIMOX offers high-quality continuous BOX layers at lower oxygen doses, reduced HF-defect densities (<0.5 cm⁻²), minimal threading dislocations (<10³ cm⁻²), and surface roughness of 3–7 Å, comparable to bonded SOI wafers. Electrical characterization using HgFET techniques confirms high electron/hole mobilities and excellent BOX breakdown properties.
The chapter also discusses the scalability of SIMOX to 300 mm wafers, improvements in implantation equipment (higher O⁺ beam currents, energy range, and reduced particle contamination), and ongoing challenges such as wafer handling, uniformity control, and cost reduction. Advanced applications of SIMOX include generic and patterned SOI for system-on-chip (SOC) integration, with successful demonstrations in IBM microprocessors and eDRAM technologies, showing comparable yield, retention times, and improved switching speeds over bulk Si devices.
In summary, SIMOX has evolved into a mature, manufacturable, and scalable method for high-quality SOI wafers, supporting advanced CMOS logic, memory, and RF applications while enabling system-level integration and future technology scaling.
OMeda (Shanghai Omedasemi Co.,Ltd) was founded in 2021 by 3 doctors with more than 10 years of experience in nanpfabrication. It currently has 15 employees and has rich experience in nanofabrication (coating, lithography, etching, two-photon printing, bonding) and other processes. We support nanofabrication of 4/6/8-inch wafers.
