Dept. of Electrical Engineering
Oregon Graduate Center
The deep level characterization of magnesium doped indium phosphide grown by organometallic vapor phase epitaxy (OMVPE) is reported. The chief motive for this work has been the applications of p-InP in optoelectronic and microwave devices. Secondly, very little use has been made, of magnesium as a p-type dopant. The properties such as low diffusivity and high solubility in III-V compounds make magnesium an attractive dopant. However, the high concentrations of Mg used in many device applications cause concern of magnesium-related deep traps being formed and affecting the device performance. Deep level transient spectroscopy (DLTS) was used to characterize deep traps present in InP:Mg samples. The theory of DLTS is discussed in detail. This method offers direct information about a host of trap parameters such as activation energy, capture cross section, concentration and the nature of the trap. This technique is capable of detecting defects having concentrations as low as ~10[superscript 12]cm[superscript -3] and is thus sensitive to trap concentrations on the 10 parts per billion scale. However, it does not provide information on the physical identity of the trap. CV and IV measurements are made on the Au-InP Schottky diodes. The net acceptor concentration barrier height and ideality factor of the diode are determined from these measurements. The relative values of these characterization methods are discussed. DLTS measurements over a temperature range of 77 Â°K - 400 Â°K revealed the presence of hole traps in InP:Mg samples. A total of three hole traps are observed having activation energies of 0.31, 0.54 and 1.16 eV from the valence band. The capture cross sections are 3.2X10[superscript -17], 1.5X10[superscript -14] and 2.7x10[superscript -7]cm2 respectively. The concentration of these traps is found to be in the range of 10[superscript 12]-10[superscript 15]cm[superscript -3]. The physical identity of the traps is merely speculated, as accurate identification requires a much more detailed study which is beyond the scope of this work. Trap H (0.31) is observed in the majority of the samples and is attributed to Mg related complex, while traps H (0.54) and H (1.16) are seen only once and are thought to be some contaminants incorporated during the growth.
Cholan, Hemavathy, "Deep level transient spectroscopy of magnesium doped indium phosphide" (1987). Scholar Archive. 251.