Thermal Treatment of Silicon Rectifiers

The effect of thermal treatment on silicon point contact rectifiers over the temperature range between 900^∘{}C and 1400^∘{}C, both in high vacuum and in an oxygen atmosphere below about 0.1 mm Hg, has been investigated by means of heating a silicon specimen directly. During the treatment above 1250^∘{}C in vacuum, the rectification is changed remarkably and is finally lost. It is recovered by successive heat treatment in oxygen. Both the creation of thermal donors or acceptors and the absorbed oxygen may be regarded as causes of these phenomena. The contact area calculated from the ohmic resistance at the non-rectifying contact is the order of 10^-6 cm².