engleski

Influence of Shallow Impurity on Steady-State Probability Function of Multilevel Deep Impurity

The deep impurity add into the n- or p-type of a semiconductor is partially ionised. The probability function used to describe the occupation of a deep energy level, is the Fermi-Dirac function into which the entropy factor is introduced; *_p for donor level or *_n for acceptor level. The entropy factors are used to adjust the calculated and measured values. An effective deep energy level was defined, depending on the predicted position of a deep level and on obtained entropy factor. Comparing the calculated and measured values for gold and platinum added into the n- and p- type of silicon, we can see that the same predicted energy level is described with the quite different entropy factor in the n- and p- type of a semiconductor. According to the obtained positions of the effective deep energy levels, it can be concluded that in the compensation between shallow and deep impurity a deep level, which is nearest to the shallow level, must be considered. The other levels are neutral. It might happen that in the n-type of semiconductor the higher acceptor level of platinum is occupied, while the lower one is empty. It seems that such a neutral energy level does not exist in the n-type, while in the p-type it does, and it is partially occupied. *=hi

multilevel deep impurity; entropy factor; deep energy level; probability function

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