Simplified method of transistor manufacture

An improved method for the manufacture of semiconductor devices which shortens the processing steps leading to metallization is disclosed. The present invention utilizes a controlled silicon etch process which allows emitters to be diffused into both the emitter and base sites. Undesired emitters are then removed from the base sites prior to metallization which enables the semiconductor devices to be manufactured in fewer numbers of steps than that required by the prior art processing techniques. The invented method for forming a contactual region in a semiconductor substrate having a planar base region comprising the steps of forming at least one opening through an insulating layer on the substrate. Next, an impurity is diffused into the substrate through the opening to form a base region. A passivating layer is then disposed over the insulating layer and the opening. A pattern is etched through the passivating layer so as to expose a selected area in the base region of the substrate. A second impurity is now diffused into the base region through the pattern forming the emitter regions. Finally, undesired emitters are removed, and the device is ready for metallization.