The role of nanoclusters in reducing hole trapping in ion implanted oxides

Effect of implanting silicon in buried oxide on the radiation hardness of the partially-depleted CMOS/SOI

“…Photoluminescence studies indicate that there are silicon nanoclusters [7] , which cause the result of the formation of electron traps in the oxide, and electrons trapped at these sites can compensate the positive charge of the trapped holes. Mrstik et al [8] have reported that implantation of silicon at high doses (1 10 15 cm -2 or higher) into the oxide, and subsequent high temperature anneal, forms electron traps located near the peak of the implant that have a very large capture cross section ( 1 10 -13 cm -2 at an applied field of 1MV/cm). When these implanted oxides are exposed to ionizing radiation, the electron traps can provide effective compensation of the positive charge due to the trapped holes.…”

Radiation hardening technology in SOI materials and devices

“…[22,23] 利用多次注 入、多次退火的工艺初步提高了SIMOX材料的抗辐 射能力, 后来该小组采用辅助注氧的办法, 进一步降 低了BOX中空穴陷阱的密度, 提高了SIMOX材料的 抗辐射性能. 1998年, Hughes等人 [24] 发现SIMOX中注 硅能够大大提高其抗总剂量能力, 并申请了相关专 利. Mrstik等人 [25] 利用硅离子注入到BOX中发现只有 当注入离子的浓度达到一定阈值时才能产生电子陷 阱来补偿辐射感生的空穴陷阱电荷. 目前Honeywell 公司采用加固SIMOX材料已经制备出抗总剂量能力 达到50 Mrad(Si)的器件 [26] .…”

Effect of Si-implantation Induced Nanocrystals on Reducing the Oxide and Interface Traps Densities of PD SOI MOSFET Under Total-dose Irradiation

“…Assuming charge neutrality of the interface traps when the Fermi energy is at midgap [11], threshold voltage shift due to irradiation-induced net positive oxide trapped charge and interface traps, respectively, are estimated from A Vo= Vmg (post-rad) -Vmg (pre-rad) (4) z Vi= V.0 (post-rad) -Vs0 (pre-rad) (5) where Vfmg is the midgap voltage, Vsr=vth-Vmg is defined as the stretchout between the threshold and midgap voltages. Equation (4) states that the threshold voltage shift due to oxide trapped charge AV0, equals to the difference between the post and pre-radiation midgap voltages. Equation (5) expresses that the threshold voltage shift due to interface traps AVi, equals to the difference between the post and pre-radiation stretchout voltages.…”

“…A number of studies [3,4] have been done to research the irradiation properties and its mechanism of siliconimplanted SIMOX and transistors fabricated on SIMOX. One possible mechanism [3] is that silicon ion implantation creates electron traps with large capture cross sections, that, when filled, compensate radiation-induced trapped positive charge in the BOX and reduce the AVth of transistors fabricated on SOI.…”

“…It could be attributed to the formation of Si nanocrystals in SiO2 matrix. Another explanation [4] indicates that positive charge trapping is largely due to proton trapping at network sites having large Si-O-Si bond angles, and implant damage creates such proton traps in the bulk of the oxide so that fewer protons are able to reach the interface, where their effect 1-4244-0047-3/06/$20.00 ©2006 IEEE. on A Vh would be much greater.…”