Effect of Growth Parameters on Iron Incorporation in Semi-Insulating LEC Indium Phosphide

On the electrical activity of Fe in LEC indium phosphide

“…As pointed out in [11], it is interesting to note that the higher the pulling rate the higher the distribution coefficient. This is in agreement with the BPS theory [13] and with the experimental findings of Wei [5] and Fornari et al [6]. Figure 1(a), (b) also contains the concentrations of active iron, Fe active = Fe I n [14,15], measured by optical absorption measurements at 1 µm.…”

“…The problem of Fe segregation has already been discussed by different authors [3,[5][6][7][8][9][10], and it appears that there is a complex correlation between growth parameters, distribution coefficient and electrical activity of Fe in bulk LEC InP. For instance, it was reported that the pulling rate and rotational speeds affect the Fe distribution coefficient [6] as well as the electrical activity of iron in LEC InP [7]. More recently, combined chemical, optical and electrical measurements on Fe-doped bulk InP showed that the electrical activity (expressed as ratio Fe active /Fe total ) of the incorporated Fe changes dramatically from top to tail of the LEC crystals [11]: the ratio was seen to be about 0.7 in the crystal top and about 0.3 towards the tail.…”

“…a concentration gradient between top and bottom of the crystals, which limits the optimal compensation ratio to a relatively small fraction of the LEC ingots. The problem of Fe segregation has already been discussed by different authors [3,[5][6][7][8][9][10], and it appears that there is a complex correlation between growth parameters, distribution coefficient and electrical activity of Fe in bulk LEC InP. For instance, it was reported that the pulling rate and rotational speeds affect the Fe distribution coefficient [6] as well as the electrical activity of iron in LEC InP [7].…”

Incorporation and electrical activity of Fe in LEC InP

“…However, due to the very small distribution coefficient, a large Fe concentration gradient exists between top and tail of the crystals, which limits the optimal compensation ratio to a relatively small fraction of the LEC crystals. The problem of Fe segregation has already been discussed in many papers [1][2][3][4][5][6][7][8][9]; however no clear correlation has so far been established between growth parameters, distribution coefficient and electrical activity of Fe in bulk LEC InP. In previous papers the effect of different growth parameters, such as pulling rate and rotational speeds, on the distribution coefficient of iron were studied [3] and some hypotheses about the electrical activity of iron in LEC InP were advanced [4].…”

“…The problem of Fe segregation has already been discussed in many papers [1][2][3][4][5][6][7][8][9]; however no clear correlation has so far been established between growth parameters, distribution coefficient and electrical activity of Fe in bulk LEC InP. In previous papers the effect of different growth parameters, such as pulling rate and rotational speeds, on the distribution coefficient of iron were studied [3] and some hypotheses about the electrical activity of iron in LEC InP were advanced [4]. Those works were partly speculative as they were mostly based on electrical measurements which did not allow a separate evaluation of the total and active iron.…”