Tunnels in Semiconductor Epitaxy

On (100) surfaces of III–V or II–VI compounds, tunnels or grooves can be grown over oxide or Mo stripes, the axes of which are in one of the two orthogonal 〈110〉 directions on the surface. One 〈110〉 direction produces grooves and the other, tunnels. By switching from n- to p-type layers at frequent intervals during growth, the mechanism can be elucidated.