| CPC H01L 29/7375 (2013.01) | 19 Claims | 

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               1. A structure comprising: 
            a heterojunction bipolar transistor comprising a collector region, a base region and an emitter region; and 
                at least one non-single-crystal semiconductor region in the collector region of the heterojunction bipolar transistor, 
                wherein the non-single-crystal semiconductor region is vertically above a sub-collector region of the heterojunction bipolar transistor and within the collector region. 
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