What is point contact diode?

Point connect diode consists of an n-type germanium or silicon (preferably germanium) wafer about 1.25 mm suare by 0.5 mm thick, one face of which is soldered to a metal and the other face has a phosphor bronze or tungsten spring pressed against it. Because of very low capacitance, point contact diode is very much suitable for high freuency applications (of the order of 10 GHz).