Doping characterization for germanium-based microelectronics and photovoltaics using the differential Hall technique

In this coming decade, complementary metal-oxide-semiconductor microelectronic devices may undergo a major change with the implementation of germanium channels. Likewise, the performance of photovoltaic cells based on elemental semiconductors will continue to be optimized. Both technologies will rely on a detailed and thorough understanding of electrical properties, and here, precise doping characterization will play a key role. The differential Hall technique combines resistivity and Hall-effect measurements with successive surface layer removal, allowing one to measure independent carrier concentration and mobility depth profiles. In this Letter, we apply the technique for both microelectronic- and photovoltaic-relevant doping structures in germanium. Controllable and uniform layer removal is achieved with tailored depth resolution (<1–20 nm) for a range of doping structures (30–600 nm).