The heterostructure barrier varactor (HBV) is a semiconductor device which shows a variable capacitance with voltage bias, similar to a varactor diode. Unlike a diode, it has an anti-symmetric current-voltage relationship and a symmetric capacitance-voltage relationship, as shown in the graph to the right. The device was invented by Erik Kollberg together with Anders Rydberg in 1989[1] at Chalmers University of Technology.