Impact of incomplete ionization of dopants on the electrical properties of compensated p-type silicon

Abstract

About the internal pressure in cavities derived from implantation-induced blistering in semi-conductors J. Appl. Phys. 110, 114903 (2011) Silicon nanocrystals doped with substitutional or interstitial manganese Appl. Phys. Lett. 99, 193108 (2011) Effect of tin doping on oxygen-and carbon-related defects in Czochralski silicon J. Appl. Phys. 110, 093507 (2011) Ion-beam mixing in crystalline and amorphous germanium isotope multilayers This paper investigates the importance of incomplete ionization of dopants in compensated p-type Si and its impact on the majority-carrier density and mobility and thus on the resistivity. Both theoretical calculations and temperature-dependent Hall-effect measurements demonstrate that the carrier density is more strongly affected by incomplete ionization in compensated Si than in uncompensated Si with the same net doping. The previously suggested existence of a compensation-specific scattering mechanism to explain the reduction of mobility in compensated Si is shown not to be consistent with the T-dependence of the measured carrier mobility. The experiment also shows that, in the vicinity of 300 K, the resistivity of compensated Si has a much weaker dependence on temperature than that of uncompensated silicon.

Incomplete ionization and carrier mobility in compensated p-type and n-type silicon

“…2(a), the experimental p 0 agrees very well with the calculated one (see [1] for details on the calculation), including in compensated Si, over the entire studied T range. This good agreement gives confidence regarding the validity of the procedure that we used to evaluate the position of the Fermi level in p-type Si.…”

“…This section presents results obtained using this procedure for the calculation of p 0 , n 0 , N − A , and N + D with N A , N D , and T as input parameters. More details on this calculation are given in [1].…”

“…This is so because as compensation increases, the net doping is reduced compared with the majority dopant concentration. As a consequence, a given fraction of nonionized majority dopants leads to a stronger relative impact on the carrier density [1]. One general rule that can be deduced from the way these four factors influence i.i.…”

“…In that respect, reducing T is equivalent to tuning the compensation level C l [see (1)], since it effectively closes the gap between the concentrations of ionized majority and compensating dopants:…”

“…For example, it is common practice when dealing with compensated Si to consider the majority-carrier density as equal to the net doping (N A -N D in p-type and N D -N A in n-type) which is equivalent to consider all dopants to be ionized. In a recent paper [1], we used numerical solution of the Poisson equation and Hall experimental data to demonstrate that neglecting Manuscript received June 5, 2012; revised July 16, 2012; accepted July 17, 2012. M. Forster is with Apollon Solar, Lyon 69002, France, with INL-INSA de Lyon, Villeurbanne 69621, France, and also with the Australian National University, Canberra, A.C.T. 0200, Australia (e-mail: forster@apollonsolar.com).…”