Growth of p-, n-amorphous oxides and application to devices

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We have prepared p-type InGaZnO4 (IGZO) films by radio frequency (RF) magnetron sputtering of targets of mixtures of ZnO and AlN powders. In the cases of sputtering of a target (7% AlN) at high pressure of 0.02 Torr, films prepared at 0.5 and 0.6% O2 atmospheres show positive Seebeck coefficients of 1.5 and 1.2 mV/K (p-type), respectively. As O2-concentration is raised up to 1%, films become insulators again. All of films prepared from targets containing 10% AlN or more are insulators irrespective of O2-concentration in atmospheres. For a p-type IGZO films, we evaluate the resistivity of 210 ohmcm, the hole-density of 7.5x1017 cm-3 and mobility of 0.4 cm2/Vs. The rectification characteristic is seen in a current vs. voltage curve of a device comprising of Au/p-type IGZO/n-type IGZO. A possible mechanism of the growth of p-type IGZO films is that Al-N clusters with lower kinetic energy are incorporated into the disordered IGZO lattice, without the dissociation of Al-N bonds.