Study On The Characteristics Of P-Rich InP Single Crystal

InP crystal has already become a promising material in the fields of microelectronicsand optoelectronics, since it possesses many good features. Semi-insulating(SI) InP withgood characters has been widely used to manufacture high frequency HEMTs, HBTs andOEICs. Fe doping SI-InP is generally used in commercial field at the present time, SI-InP can also be got through annealing undoped-InP. It has been shown that P-rich InP can get SI characteristic more easily by annealing. But the preparation of P-rich InP is still not mature up to now, there are many imperfections on the wafers, such as small holes, dislocations, defects, which affect the applications of P-rich InP severely.The characteristics of P-rich InP crystal was studied by Photoluminescence Mapping(PL), X-ray Diffraction(XRD), Energy Dispersive Spectrometer (EDS) in this paper. Thesample used was prepared by the method of P-injection in-situ synthesis and liquid encapsulated Czochralski (LEC). PL Mapping measurements showed that the photoluminescence characteristics of P-rich InP wafer was ununiform. In the center and edge of the wafer,the wavelength of PL peak was shorter, the intensity of PL peak was much lower, theFWHM of PL peak was much bigger, compared to other parts of the wafer. The resultsrevealed that these parts might have worse crystallization quality and more defects, suchas V_In, P_In, P_i, V_InH₄. XRD measurements showed that the edge of the wafer with moreholes on it, had larger lattice constant, larger diffraction peak FWHM, compared to otherparts. So the edge of the wafer had poor crystallization quality. EDS measurements showed that the distribution of the content of P atoms and In atoms was also ununiform. On the edge and around the holes of the wafer, the content of P atoms was much higher.The poor uniformity of the content of P atoms and In atoms had influenced the distributions of band gap, defects and photoluminescence characteristics on P-rich InP wafer.