Junctions in vapor-grown germanium

The "closed-tube" process for the epitaxial vapor growth of Ge by the Ge-I2disproportionation reaction has the advantage of ease of tending and high purity. The "open-tube" process offers more flexibility in doping and better thickness control. In either case, the Ge produced is comparable in most respects to melt-grown Ge and is suitable for device applications. Alloyed and diffused junctions in vapor-grown Ge are equivalent to similar junctions in melt-grown Ge. Junctions grown from the vapor are not always similar to junctions grown from the melt; for example, impurity concentration gradients may be varied more widely. Because of the relatively low temperatures involved and the growth mechanism itself, various kinds of masking and matrix formation are feasible.