The Influence of High Pressure Oxidation on Boron Redistribution in LOCOS Structures

Abstract

As device dimensions approach 1 ~m, narrow channel effects are becoming more and more critical. In a LOCOS structure, these effects are essentially due to lateral diffusion of the field threshold implant during oxidation. EBIC, SIMS, and preferential chemical etching have been used to investigate the effects of high pressure oxidation on lateral and in-depth diffusion of boron. It has been found that lateral and vertical diffusion of boron is reduced by 0.20 and 0.33 ~m, respectively, when the pressure increases from 1 to 20 bar. For a 3 t~m linewidth test device, the observed reduction of the lateral diffusion of boron with increased pressure is shown to correspond to a 22% increase in the width of the active regions. The actual shape of the boron-doped region under the bird's beak has been deduced from EBIC measurements and preferential chemical etching within 0.06 ~m accuracy. In addition, the boron segregation coefficient at the Si/SiO2 interface is given as a function of pressure.) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 130.88.90.140 Downloaded on 2015-03-30 to IP i Courtesy of Dr. P. L. F. Hemment, Surrey University, Guildford, Engl~nd. ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 130.88.90.140 Downloaded on 2015-03-30 to IP

Electrical Properties of Silicon Dioxide Films Fabricated at 700°C: III . High Pressure Thermal Oxidation

“…This results in a highly defective top silicon layer after a high temperature anneal, typically at 1150~ This residual top silicon layer is only 100-400 nm thick (4-6), depending on the implant energy and dose. If this top residual silicon layer is too thin, it may be necessary to grow an epitaxial silicon layer to increase the thickness of the top silicon layer (7,8).…”

“…Significantly reduced oxidation temperatures have been achieved using thermal oxidation of silicon at elevated pressures of either steam (2,4,5) or dry oxygen (1,6,7). Additionally, reductions in arsenic and boron diffusion have been demonstrated using high pressure steam to reduce oxidation temperatures (8,9). A reduction in silicon stacking faults has also been obtained using high pressure steam (10).…”

Annealing Characteristics of Ultrathin Silicon Oxides Grown at Low Temperatures

“…While high-pressure oxidation for field oxides (14,15) and interpoly oxides (2,12) has been explored to some extent, ultrathin gate oxides (<10 nm) formed by this technique have received very little attention. This is due to the poor quality of low-temperature oxides reported so far (16).…”