Production-Worthy USJ Formation by Self-Regulatory Plasma Doping Method

A new method of plasma doping that achieves tight control on dosimetry and uniformity has been developed. It uses a self-regulatory behavior of plasma processes that brings high accuracy on dose control and uniformity within 1.5%. The largest advantage of this self-regulatory plasma doping (SRPD) is that the accuracy of the process control is much less dependent on the uniformity of the plasma, which makes a revolutionary difference to the plasma process as it becomes free from the primary hardware constraint. A typical doping of boron using B2H6/He gas mixture at dose of 1x1015 ions/cm2 can achieve a uniformity of less than 1.5% across a 300mm silicon wafer when the plasma uniformity above the wafer plane is as poor as 10%. The SRPD process also forms very abrupt junctions such as less than 2nm/decade at the junction depth of 10nm due to an instantaneous amorphization of the wafer surface within the first 5 seconds of the process duration. Combined with the throughput advantage at low energy against the conventional ion implantation, the SRPD offers an ideal performance for USJ formation for 45nm technology node and beyond