Effect of tilt angle variations in a halo implant on V/sub th/ values for 0.14-(mu)m CMOS devices

Sensitivity of critical transistor parameters to halo implant tilt angle for 0.14-(mu)m CMOS devices was investigated. V/sub th/ sensitivity was found to be 3% per tilt degree. A tilt angle mismatch between two serial ion implanters used in manufacturing was detected by tracking V/sub th/ performance for 0.14-(mu)m production lots. Even though individual implanters may be within tool specifications for tilt angle control (+-0.5(degree) for our specific tool type), the relative mismatch could be as large as 1(degree), and therefore, result in a V/sub th/ mismatch of over 3% from nominal. The V/sub th/ mismatch results are in qualitative agreement with simulation results using SUPREM and MEDICI software.