Embodiments of the invention include a method for forming a tunable semiconductor device and the resulting structure. The invention comprises forming a semiconductor substrate. Next, pattern a first mask over the semiconductor substrate. Dope regions of the semiconductor substrate not protected by the first mask to form a first discontinuous subcollector. Remove the first mask. Pattern a second mask over the semiconductor substrate. Dope regions of the semiconductor substrate not protected by the second mask and on top of the first discontinuous subcollector to form a second discontinuous subcollector. Remove the second mask and form a collector above the second discontinuous subcollector. Breakdown voltage of the device may be tuned by varying the gaps separating doped regions within the first and second discontinuous subcollectors. Doped regions of the first and second discontinuous subcollectors may be formed in a mesh pattern.