Systems for selective deposition using a sacrificial capping layer

A system comprising:

• one or more reaction chambers;
• a gas injection system fluidly coupled to at least one of the one or more reaction chambers;
• a first gas source;
• a second gas source;
• a third gas source;
• an exhaust source;
• and
• a controller,
• wherein the controller is configured to control gas flow into the gas injection system to selectively form a p-type doped silicon germanium layer overlying a first surface of a substrate relative to a second surface of the substrate by performing the steps of:
• depositing a p-type doped silicon germanium layer overlying the first surface and the second surface, the p-type doped silicon germanium layer comprising gallium;
• depositing a cap layer overlying the p-type doped silicon germanium layer;
• selectively etching the cap layer and the p-type doped silicon germanium layer overlying the second surface;
• and
• repeating the steps of depositing the p-type doped silicon germanium layer, depositing the cap layer, and selectively etching the cap layer and the p-type doped silicon germanium layer overlying the second surface to thereby selectively form the p-type doped silicon germanium layer overlying the first surface relative to the second surface.