A semiconductor transistor has a structure including a semiconductor substrate, a source region, a drain region and a channel region in between the source region and the drain region. A gate is provided above the channel region. A silicon nitride protective layer is provided over the source region and the drain region, along with a silicon nitride cap over the gate region. The silicon nitride protective layer is configured to allow punch-through of the protective layer after source and drain openings are created, while preventing etching through the cap above the gate. The self-aligned source, drain and gate contacts are formed while protecting the source and drain salicide using the silicon nitride protective layer and gate cap.