Reduction of charge trappings and electron tunneling in SIMOX by supplemental implantation of oxygen

Abstract

The reduction of excess-silicon related defects in SIMOX by the supplemental implantation of oxygen has been examined. The supplemental implant is 6% of the oxygen dose used to form the buried oxide, and is followed by a 1000°C anneal, in contrast to the >130O0C anneal used to form the buried oxide layer of SIMOX. The defects examined include shallow electron traps, deep hole traps, and silicon clusters. The radiation-induced shallow electron and deep hole trapping are measured by cryogenic detrapping and isothermal annealing techniques. The low-field (3 to 6 MV/cm) electron tunneling is interpreted as due to a two phase mixture of stoichiometric SiO, and Si clusters a few nm in size. Single and triple SIMOX samples have been examined. All of the defects are reduced by the supplemental oxygen processing. Shallow electron trapping is reduced by an order of magnitude. Because of the larger capture cross section for hole trapping, hole trapping is not reduced as much. The low-field electron tunneling due to Si clusters is also significantly reduced. Both uniform and nonuniform electron tunneling have been observed in SIMOX samples without supplemental processing. In samples exhibiting only uniform tunneling, electron capture at holes has been observed. The nonuniform tunneling is superimposed upon the uniform tunneling and is characterized by current spiking.

The radiation hardness of the nitrogen-fluorine implanted buried oxide layer in silicon-on-insulator materials against higher total dose irradiation

“…Because the capture cross section of electron traps is much smaller than that of hole traps [21], it is reasonable to assume that ΔNh would be close to a saturation value at the high total doses, while ΔNe slowly increases with the doses. On the other hand, it can be seen from Fig.…”

Influence of total-dose radiation on the electrical characteristics of SOI MOSFETs

“…For SIMOX wafers, other implant and anneal conditions have been explored to reduce radiation-induced charge trapping. For instance, buried oxides formed using supplemental [38][39][40][41][42] and multiple [43] implants and anneals show less radiation-induced degradation than buried oxides formed with a single implant. Both the number of radiation-induced interface traps and the concentration of oxide-trapped charge were significantly reduced for buried oxides formed using multiple implants [43].…”

Research on ion implantation effect on SIMOX material modification technique by X-ray photoelectron spectroscopy

“…To build up a reliable mass production technique, there is increasing demand for quick evaluation of the electrical properties of as-fabricated SOI wafers. The pseudo-MOSFET (W-MOSFET) technique, which was developed by Cristoloveanu et al [10], was proposed to characterize SOI wafers efficiently and rapidly [1,2]. It is the simplest kind of silicon-on-insulator (SOI) transistors and can be obtained on all SOI structure immediately.…”

“…Moreover, the buried oxide in SOI wafers limits the total fluence radiation tolerance of SOI materials. To improve the total fluence radiation tolerance for SIMOX SOI wafers, many methods have been explored, for instance, supplemental implants [1][2][3][4][5], multiple implants [6], lowering the implantation fluence of oxygen ions [7] and nitrogen implantation [8,9], etc. Among the measurement methods, MOSFET is the most frequently used.…”