The influence of low-energy argon implantation and out-diffusion heat treatments on hydrogen enhanced thermal donor formation in p-type Czochralski silicon

Hydrogen enhanced thermal donor (TD) formation was investigated in p-type Czochralski (Cz) silicon treated either by low-energy (6 keV) Ar implantation or high temperature annealing and in both cases by a subsequent plasma hydrogenation. The Ar implantation was done at 100 or 550 degrees C at various doses up to 3.10(18) cm(-2). A one-step "high" or a three-step "high-low-high" annealing were applied to create a denuded zone (DZ). Spreading resistance probe (SRP) measurements were used for the samples characterization. It is shown that the incorporation of hydrogen at 400 degrees C from a DC hydrogen plasma into pre-treated p-type Ct Si leads to the formation of a n-type region and of p-n junctions in the hydrogenated region near the wafer surface. It was found that the depths of p-n junctions in different p-type Ct substrates are dependent on the time of hydrogenation, posthydrogenation treatments and on the pre-treatment history of the samples. The increase of the Ar implantation dose leads to an increase of the rate of TD formation near the surface while high temperature pre-treatments result in a decrease of the TD formation rate. In the former case the formation of a buried n-type region was observed. It can be concluded that the disordered region does not inhibit the hydrogen penetration into the Ct Si wafer at 400 degrees C and therefore does not prevent the TD formation. The mechanism of hydrogen enhanced TD formation and the depth resolved SRP measurements can be used to elucidate the distribution of interstitial oxygen in Ct Si after different heat treatments of the samples and for a qualitative characterization of the DZ.