Hydrogen-resist lithography with the tip of a scanning tunnelling microscope can be used to fabricate atomic-scale dopant devices in silicon substrates and could potentially be used to build a dopant-based quantum computer. However, all devices fabricated so far have been based on the n-type dopant precursor phosphine. Here, we show that diborane can be used as a p-type dopant precursor, allowing p-type and bipolar dopant devices to be created. Characterization of diborane δ-layers reveals that similar mobilities and densities can be achieved as for phosphine, with sheet resistivities as low as 300 Ω □⁻¹. Scanning tunnelling microscope imaging and transport measurements of a 5.5-nm-wide p-type dopant nanowire give an estimated upper bound of 2 nm for the lithographic resolution of the p-type dopant profiles. By combining our p-type doping approach with established phosphine-based n-type doping, we fabricate a 100-nm-wide p–n junction and show that its electrical behaviour is similar to that of an Esaki diode.

带有扫描隧道显微镜尖端的抗氢光刻技术可用于在硅基板上制造原子级掺杂剂设备，并可潜在地用于构建基于掺杂剂的量子计算机。但是，到目前为止制造的所有器件都基于n型掺杂剂前体膦。在这里，我们表明乙硼烷可以用作p型掺杂剂前体，从而可以创建p型和双极性掺杂剂器件。乙硼烷δ层的表征表明，与磷化氢相比，可以实现类似的迁移率和密度，薄层电阻低至300Ω□ ^-1。扫描隧道显微镜成像和5.5 nm宽的p型掺杂剂纳米线的传输测量得出，对于p型掺杂剂轮廓的光刻分辨率，估计的上限为2 nm。通过将我们的p型掺杂方法与已建立的基于膦的n型掺杂相结合，我们制造了一个100 nm宽的p–n结，并证明了其电学行为与Esaki二极管相似。