Total dose radiation response of modified commercial silicon-on-insulator materials with nitrogen implanted buried oxide

Abstract

Nitrogen ions of various doses are implanted into the buried oxide (BOX) of commercial silicon-on-insulator (SOI) materials, and subsequent annealings are carried out at various temperatures. The total dose radiation responses of the nitrogen-implanted SOI wafers are characterized by the high frequency capacitance-voltage (C-V ) technique after irradiation using a Co-60 source. It is found that there exist relatively complex relationships between the radiation hardness of the nitrogen implanted BOX and the nitrogen implantation dose at different irradiation doses. The experimental results also suggest that a lower dose nitrogen implantation and a higher post-implantation annealing temperature are suitable for improving the radiation hardness of SOI wafer. Based on the measured C-V data, secondary ion mass spectrometry (SIMS), and Fourier transform infrared (FTIR) spectroscopy, the total dose responses of the nitrogen-implanted SOI wafers are discussed.

Low frequency noise and radiation response in the partially depleted SOI MOSFETs with ion implanted buried oxide

“…The value of τ 0 is typically taken to be equal to 10 −10 s for traps distributed up to 5 nm. Equation (5) states that the probability of penetration into the buried oxide decreases exponentially with distance. The extracted trap density profiles for these SOI devices with and without ion implantation are shown in Fig.…”

“…[3,4] It has been reported that high fluence ion implantation (such as Al, Si, P or Ge) into the buried oxide can be used to reduce the shift in back gate threshold voltage during exposure to ionizing radiation by creating electron traps with a very large capture cross section and compensating for trapped positive charges when being filled with electrons. [4][5][6][7][8][9][10] For example, Mrstik et al [6] studied charge trapping in thermal oxides implanted with up to 5×10 15 cm −2 of Al, Si, P. They found that the capture cross section (1×10 −13 cm 2 ) is large in electron trap formed at the highest implant doses, while the shift of flat-band voltage following hole injection decreases, which indicates a reduction of hole trapping near the Si-SiO 2 interface. However, near interface shallow electron traps are created by ion implantation, which leads to large bias instability at the interface between silicon and buried oxide.…”

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

“…Seeing that the F implanted BOX displays its increased radiation hardness [13] and so does the N implanted BOX in our previous researches [15,16], both N and F ions were implanted into the BOX of the separation by implanted oxygen (SIMOX) SOI materials in this work, and the total dose radiation responses of the modified BOX layers were observed with the capacitance-voltage (C-V) technique. Based on the C-V characterization, the significantly improved radiation hardness of this N-F implanted BOX was demonstrated, in spite of the relatively complex radiation responses depending on the specific processes which need further improving, and the related mechanisms were discussed.…”

“…First, N ions were implanted into the BOX layers of the four SOI wafers denoted as W1-W4, respectively, using a dose of 10 16 cm −2 at an energy of 90 keV with the wafers maintained at 300°C, and the implanted wafers W2-W4 were annealed at 1100°C in N2 atmosphere for 0.5, 1.0, 1.5 h, respectively. Specially, the wafer W1 did not anneal subsequently to N implantation, so as to exhibit the anneal role to a greater extent in changing the radiation response of the modified BOX.…”