Influence of oxygen RIE on silicon device

High density plasma etching such as electron cyclotron resonance (ECR) has become a key technology for the fabrication of integrated circuits since it guarantees fine pattern transfer. The ECR etching process is, moreover, expected to induce less silicon damage in oxide etching such as contact hole etching because of its high selectivity. A high selectivity etching process generates a carbon containing residue film on the silicon surface (Oehrlein, 1989). To fix this problem, a contact hole etching process using such ECR plasma is frequently followed by an in-situ ECR-O₂-RIE process in order to remove the residue film. The O₂-RIE has process convenience in terms of etch rate controllability and anisotropy. However, the influence of the O₂-RIE on the silicon substrate has not been clearly understood. In this work, we investigated the influence of the O₂ -RIE on silicon devices using a method based on bipolar transistor characteristics. This method can detect shallow energy-level-defects and slight defects, and then promise high sensitivity in estimating the silicon damage (Nakanishi et al., 1996 and 1997). To aid further understanding, TEM analysis was employed. In addition, the silicon damage induced by the contact etching was also discussed