Formation of etch-stop structures utilizing ion-beam synthesized buried oxide and nitride layers in silicon

With advanced micromechanical devices the ability to form, with highly reproducible results, useful etch-stop layers is becoming increasingly important. A novel etch-stop method of fabricating thin silicon structures is proposed. The approach is based on the use of buried compound layers produced by the implantation of reactive O⁺ and N⁺ ions into single-crystal silicon. The etch-stop properties of these layers are assessed and a conceivable mechanism for the decrease of etch rate for ethylenediamine—pyrocatechol—water(EPW) solution is outlined. It is demonstrated that such substrates incorporating implantation-synthesized oxide or nitride layers have relevance to the micromachining of silicon.