EFFECT OF REACTIVE ION ETCHING AND POSTETCHING ANNEALING ON THE ELECTRICAL CHARACTERISTICS OF INDIUM-TIN OXIDE SILICON JUNCTIONS

Indium tin oxide (ITO) films were deposited onto p-type Si wafers with radio frequency (r.f.) magnetron sputtering. The effect of the silico n surface treatment with reactive ion etching (RIE) on the current-vol tage (I-V) and capacitance-voltage (C-V) characteristics of the ITO/Si junction are investigated. When the Si substrate is etched by RIE pri or to the deposition of ITO film, the I-V characteristics of the ITO/p -Si junction transfer from an ohmic contact for the unetched-Si to a r ectifying contact for the etched Si. In addition, the barrier height, ideality factor, and series resistance increase with increasing etchin g power. This is attributed to the net positive ion charge and defects on the damaged surface. Thermal annealing can eliminate the damage ca used by RIE. The I-V curves of ITO/etched p-Si become more ohmic as sa mples are annealed in N-2 at 300 degrees C. Secondary ion mass spectro scopy (SIMS) depth profiles indicate that some impurity defects migrat e and/or disappear after post-etching annealing. (C) 1998 Chapman & Ha ll.