Minimum oxygen dose for reliable application of SIMOX

Silicon-on-insulator structures were fabricated by several high dose oxygen implantations in a dose range from 2.0 × 1017 cm−2 to 2.4 × 1018 cm−2. The thickness of the buried oxide was determined by preferential etching followed by measurements of the step heights. As expected, the thickness of the buried layer increased linearly with the implanted dose. Large-area capacitors using the silicon film as one electrode and the substrate as the other, were produced in a LOCOS process. These devices rendered possible the study of the electrical properties of the buried oxide by capacitance-voltage and current-voltage (C(V) and I(V)) measurements. Knowledge of the dose dependence of the buried oxide properties allow adjustment of the minimum implantation dose necessary to comply with given requirements.