Al ion implantation

Al implantation (500 nm thick box profile by multiple implantation)
 

Dependence on implantation temperature [1]

  • optimum implantation temperature: 400°C
  • residual defects after high temperature annealing (1550°C): 
    dislocation loops mainly in the pn-junction region
  • for implantation temperature > RT no correlation between electrical and structural properties.
Fig. 1  Resistivity vs. implantation temperature after different annealing temperatures and
annealing treatments (plateau concentration: 5x1019 cm-3)
 
 

Dependence on the implanted Al concentration and annealing [2]

  • For high Al plateau concentration strong dependence on the annealing temperature.
  • Flash lamp annealing effects the highest electrical activation [3]

Fig. 2  Carrier concentration vs. Al-plateau concentration and
annealing treatment (Timpl = 400°C).
 
 

Spreading resistance profiling [4]

The spreading resistance (SR) method is a powerful tool to determine depth profiles of electrical active dopants in semiconductors. It is used as a routine method for Silicon. However, for wide band gap semiconductors problems with the high barrier resistance occur. Aim of our work was to apply the method for p-type 6H – SiC.
Using ion sputtering with 2 keV Ar ions the barrier resistance was lowered and SR profiles were obtained for Al doped 6H - SiC.
 

Fig. 3  Spreading resistance distribution of Al-implanted 6H-SiC
 (5x1020 Al cm-3, Timpl.  = 400°C)
 
 

References

[1] D. Panknin, H. Wirth, A. Mücklich, W. Skorupa
     Materials Science and Engineering B 61-62 (1999) 363
[2] D. Panknin, H. Wirth, W. Anwand, G. Brauer, W. Skorupa
     Proc. Intern. Conf. on SiC and Related Materials, Raleigh (NC), October 10-15, 1999
[3] H. Wirth, D. Panknin, W. Skorupa, E. Niemann
     Appl. Phys. Letters 74 (1999) 979
[4] T. Gebel, D. Panknin, R. Riehn, S. Parascandola, W. Skorupa
     Proc. Intern. Conf. on SiC and Related Materials, Raleigh (NC), October 10-15, 1999