Temperature implantation

Flux effect for different implant temperatures schematic... 

Figure 4.2 Schematic illustration of the flux effect at four different implant temperatures for a constant fluence.

In this chapter, we review the current status of doping of SiC by ion implantation. Section 4.2 examines as-implanted depth profiles with respect to the influence of channeling, ion mass, ion energy, implantation temperature, fluence, flux, and SiC-polytype. Experiments and simulations are compared and the validity of different simulation codes is discussed. Section 4.3 deals with postimplant annealing and reviews different annealing concepts. The influence of diffusion (equilibrium and nonequilibrium) on dopant profiles is discussed, as well as a comprehensive review of defect evolution and electrical activation. Section 4.4 offers conclusions and discusses technology barriers and suggestions for future work. 

Figure 4.6 shows data that summarize the current knowledge about damage accumulation in SiC versus ion mass and implantation temperature. Almost all the experimental data that will be discussed from here on concerns the Si sublattice. In a first approximation, they can be considered representative of the whole SiC network because it has been observed that damage accumulations on the Si and C sublattices are rather similar (see Figure 4.4). The data in Figure 4.6 refer to both 3.5° off-axis 6H-SiC and 8° off-axis 4H-SiC wafers implanted at 60° off the wafer normal. The dose rate was in the range 1 X 10 cm" sec" to 8 x 10 cm secbut...

Figure 4.5 (a) Comparison between the computed and measured displaced profiles SRIM-97 simulation versus experimental data. (From [63]. 1999 Elsevier B.V. Reprinted with permission.) (b) values for the C and Si sublattices in 6H-SiC versus ion dose for 300K implantation temperature. (From [31]. 2002 Elsevier B.V. Reprinted with permission.) (c) for the Si sublattice in 6H-SiC versus ion dose and ion mass for 180-190K implantation temperature. (From [63]. 1999 Elsevier B.V. Reprinted with permission.)... 

Figure 4.6 Disorder at the damage peak for the Si sublattice versus (a) the ion mass (From [63]. 1999 Elsevier B.V. Reprinted with permission.) and (b) the implantation temperature (From [5]. 1999 Elsevier B.V. Reprinted with permission.) Part (c) shows the increase of the dose for amorphization versus increasing implantation temperature (From [35]. 2003 American Institute of Physics. Reprinted with permission.).

Figure 4.7 Influence of the dose rate on damage accumulation in 4H-SIC for fixed ion mass and ion energy (a) damage at the peak of the Si sublattice versus increasing dose rate and increasing implantation temperature (b) evaluation of the energy activation for the phenomenon responsible of the shift versus temperature shown in part (a). (From [26], 2003 American Institute of Physics. Reprinted with permission.)...

Ohno, T., and K. Amemiya, Influence of Implantation Temperature and Dose Rate on Secondary Defects Eormation in 4H-SiC, Mater. Sci. Forum, Vol. 389-393, 2002, pp. 823-826. 

It is also possible to use an implanted temperature sensor to monitor temperature remotely and without using this type of invasive measurement. For example, microchip transponders (ELAMS, BioMedic Data Systems, Inc., Seaford DE, USA) have been shown to reliably monitor temperature without significant difference from rectal temperature measurements (35). 

FIGURE 5 The resistance of a number of polymer compositions implanted at 50 keV to a dose of 1 X 10 ions/cm . Note that the resistance first increases with increasing dose rate, then decreases. The trend at higher dose rates is attributed to higher implant temperatures. 

The effect of implantation temperature in nonelectroactive polymers has been studied by various authors [IJ. Davenas 87] established that the metallic conduction in... 

Furthermore (88), during low energy implantation, we noticed that the effect of implantation temperature on the evolution of both conductivity and thermoelectric power, according to the dose, is not important with heavy ions (such as Cs and I) but is stronger for sodium ions (at low temperature, 10 ions/cm-, where, V remains low and much lower than 10 /xV/K). 

Figure 19 Dependence of the density of residual defects in N2 -implanted 3C-SiC on implantation temperature. (From Ref. 104).

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