A Method to Detect Oxygen Precipitates in Silicon Wafers by Highly Selective Reactive Ion Etching

Abstract

This work presents a new method for detecting oxygen precipitates in Si wafers. The method utilizes a highly selective reactive ion etching process. When a Si wafer containing oxygen precipitates is etched under the condition of high selectivity of silicon over silicon oxide, needle-shaped silicon cones can be formed below the oxygen precipitates, because they are hardly etched. Using this method, the depth distribution of the oxygen precipitates having diameters of at least 15 nm has been successfully evaluated by evaluating the number and height of the cones. It was also demonstrated that this method is effective in detecting oxygen precipitates remaining in the denuded zone.

The impact of platelet oxygen precipitates in silicon on the junction leakage current and the interstitial oxygen loss

“…Due to the formation of OPs the internal gettering (IG) process is possible but, conversely, the presence of a layer of OPs results in an increase of the diffusion current component of the junction leakage [3]. Moreover, the density of OPs within the denuded zone is lowered, but they can be still observed [4]. When OPs are considered to be distributed within the bulk silicon, the morphology of OPs must be accounted for.…”

Measurements of Size, Morphology, and Spatial Distribution of Oxygen Precipitates in Si Wafers Using RIE

“…In our previous paper, 9 we reported that the RIE technique was useful in measuring the depth distribution of oxygen precipitates and evaluating the quality of the denuded zone of Si wafers and that the detected precipitate size was about 15 nm. In this paper, the detectable oxygen precipitate size limit of the RIE technique was estimated using wafers containing oxygen precipitates with different sizes.…”

“…9 In this technique, RIE with a high Si/SiO 2 selectivity is performed on a wafer containing oxygen precipitates, which are consequently detected as needle-shaped Si cones. 9 In this technique, RIE with a high Si/SiO 2 selectivity is performed on a wafer containing oxygen precipitates, which are consequently detected as needle-shaped Si cones.…”

“…We have recently proposed a new technique for detecting oxygen precipitates in Si wafers, which utilizes a reactive ion etching ͑RIE͒ process with a high Si/SiO 2 selectivity. 9 In this technique, RIE with a high Si/SiO 2 selectivity is performed on a wafer containing oxygen precipitates, which are consequently detected as needle-shaped Si cones. The detection principle of this technique and a typical scanning electron microscopy ͑SEM͒ image of such Si cones are shown in Fig.…”

A new approach to detect small-sized oxygen precipitates in Si wafers using reactive ion etching

“…We have recently proposed a new technique for detecting oxygen precipitates in Si wafers that utilizes highly selective reactive ion etching (NE) [6]. In this technique, RIE with a high Si/SiO, selectivity is performed on a wafer containing oxygen precipitates, which are consequently detected as needle-shaped Si cones.…”