Image Number 7 for United States Patent #7041564.
According to one exemplary embodiment, a bipolar transistor comprises a base having a top surface. The bipolar transistor further comprises a sacrificial post which, in one exemplary embodiment, is situated between first and second link spacers. The bipolar transistor also comprises a conformal layer situated over the sacrificial post. The conformal layer may comprise silicon oxide, for example. According to this exemplary embodiment, the bipolar transistor further comprises a sacrificial planarizing layer situated over the conformal layer, the sacrificial post, and the base. The sacrificial planarizing layer has a first thickness in a first region between the first and second link spacers and a second thickness in a second region outside of the first and second link spacers, where the second thickness is generally greater than the first thickness. Another embodiment is a method that achieves the above-described bipolar transistor.