On the Uniformity of Phosphorus Emitter Concentration for Shallow Diffused Transistors

The variables affecting the uniformity of sheet resistance for a two‐step shallow phosphorus emitter diffusion were examined. The source used was . The uniformity of sheet resistance (and hence surface concentration) was predominantly dependent on the variables during the deposition process. These were oxygen and nitrogen flow, wet nitrogen flow and temperature of deposition. The latter ranged from 700° to 860°C. A comparison was made of the variables that affect phosphorus, boron, and arsenic depositions. The behavior of oxygen on the sheet resistance profile during phosphorus deposition was different from that observed for boron and arsenic depositions.