TABLE OF CONTENTS D.K. Sadana
Silicon-on-insulator (SOI) based devices and circuits increase chip speed, lower voltage operation and enhance resistance to cosmic ray induced soft error events. Advanced CMOS logic and memory applications require ultra-thin SOI, with Si layers of less than 1000 . The most direct and powerful method to form cost efficient SOI is by separation of implanted oxygen (SIMOX). This method utilises O + implantation into a heated Si substrate (>200 C) at doses >2 10 17 cm ?2 followed by high temperature annealing (above 1300 C), to form a buried SiO 2 layer. Recent advances in improving SIMOX quality by the modified low-dose process (MLD) will be described. It will be shown that the quality of the modern MLD SIMOX is comparable to that of bonded SOI. Functional products including microprocessors, SRAM memories and high frequency RF circuits utilising IBM s 0.18 m and 0.13 m CMOS technologies show equivalent yield on both bonded SOI and MLD SIMOX.
Silicon-on-insulator (SOI) devices were first developed for early satellite and man-in-space exploration systems in the 1960s. The main advantage of SOI devices was their resistance to ionisation from solar wind radiation and voltage isolation of the chips. Most of the early SOI devices were made with silicon-on-sapphire (SOS) wafers. Replacement of SOS by SOI was accomplished by the SIMOX process (separation by implantation of oxygen) in the 1970s [1]. Today, SOI wafers are produced mainly by two methods, namely, wafer bonding [2] and SIMOX.
Material technology to...
