|
Abstract
|
|
|---|---|
| In the course of reducing the cost of photovoltaic solar energy, cheaper solar grade silicon materials of lower purity are being developed for the Si photovoltaic industry. Their use demands a more effective impurity reduction during solar cell processing in order to maintain or even increase solar cell efficiencies. It has been shown by different researchers that low temperature treatments below 700oC after P-diffusion gettering (PDG) can lead to higher charge carrier lifetimes and thus, to better device performances. So far, the drawback of the investigated treatments has been the long processing times of up to several hours. In the present work, we show that an enhanced reduction of Fe and a considerable increase in electron lifetimes can yet be achieved for a 15 min anneal at the appropriate temperature. In comparison to a standard gettering step at 850oC during 20 min, the final concentration of interstitial Fe has been reduced by one order of magnitude from 3e11cm-3 down to 5e10cm-3. Thus, this short extended PDG bears a great potential for its implementation in industrial solar cell fabrication processes. The short annealing step is shown to be effective, only if it directly follows the PDG step, without intermediate cool down to room temperature. The experimental results are contrasted with simulations that predict that the optimum temperature is higher for shorter annealing times. Additionally, the effect of the modified PDG on other impurities is also discussed | |
|
International
|
Si |
|
Congress
|
EMRS-2010 |
|
|
960 |
|
Place
|
Estrasburgo |
|
Reviewers
|
Si |
|
ISBN/ISSN
|
0000-0000 |
|
|
|
|
Start Date
|
07/07/2010 |
|
End Date
|
11/07/2010 |
|
From page
|
0 |
|
To page
|
0 |
|
|
Proceedings |