Electron paramagnetic resonance study of thermal donors in Fe-doped InP

Abstract

The effect of thermal annealing of semi-insulating InP wafers in the 660–820 °C temperature range under SiNx capping condition is studied by electron paramagnetic resonance (EPR) spectroscopy. The annealing leads to the formation of electrically active, deep thermal donors with total defect concentrations up to 1016 cm−3. The thermal donors are of intrinsic origin. By transient EPR spectroscopy the activation energies for electron emission of the dominant thermal donors were determined to be 0.40 and 0.14 eV, respectively.

Electrical conduction in annealed semi-insulating InP

“…This result is consistent with previous works that have shown thermal donor formation in Fe-doped SI InP. [11][12][13][14][15] It is also observed that the breakdown field of annealed Fe-doped SI InP decreases significantly. Indeed, the breakdown field of annealed undoped SI InP is found to be as low as 2.8 kV/cm, giving a negative appreciation of this material.…”

“…It has been found that intrinsic donor defects are formed when Fedoped InP is annealed at high temperature. [11][12][13][14] Our recent work has confirmed the formation of donor defects. 15 Indeed, the resistivity of annealed SI InP is found to decrease due to the formation of such defects.…”

“…15 Indeed, the resistivity of annealed SI InP is found to decrease due to the formation of such defects. 11,13,14 As expected, the resistivity change also depends on the concentration of neutral Fe 3ϩ in the as-grown Fe-doped InP. 11 Direct measurement of the Fe 2ϩ concentration in as-grown and annealed Fe-doped InP indeed confirms this speculation.…”

“…11 Direct measurement of the Fe 2ϩ concentration in as-grown and annealed Fe-doped InP indeed confirms this speculation. 13 As discussed above, the annealing of Fe-doped InP results in the formation of donor defects, causing the concentration of Fe 2ϩ to increase. This fact on its own gives sufficient explanation of the results of I -E measurements reported in this work, since the TF process is dependent on the availability of empty Fe 3ϩ traps.…”

Recent Research Results on Deep Level Defects in Semi-Insulating InP-Application to Improve Material Quality

“…The deep level defects in the SI-InP influence electrical compensation, destroy lattice perfection, enhance dislocation climb, etc. Besides, it has been found that the defects lead to thermal donor formation in annealed SI-InP [4,7,8], resulting in resistivity decreasing and thermal stability is destroyed. Thus, it is important to avoid the formation of the deep level defects and improve the quality of the Fe-doped SI-InP.…”