AVS 45th International Symposium
    Electronic Materials and Processing Division Thursday Sessions
       Session EM1-ThA

Paper EM1-ThA3
Reliability of Ultra-thin Gate Dielectric formed with Nitrogen Implantation and Thermal Oxidation

Thursday, November 5, 1998, 2:40 pm, Room 314/315

Session: Dielectrics
Presenter: Y. Ma, Bell Laboratories, Lucent Technologies
Authors: Y. Ma, Bell Laboratories, Lucent Technologies
M.S. Carroll, Bell Laboratories, Lucent Technologies
F. Li, Bell Laboratories, Lucent Technologies
C.T. Liu, Bell Laboratories, Lucent Technologies
C.Y. Sung, Bell Laboratories, Lucent Technologies
M.M. Brown, Bell Laboratories, Lucent Technologies
Correspondent: Click to Email
Traditionally nitrogen was incorporated into oxide through oxidation or post-oxidation annealing in N@Sub 2@O or NO. With a well engineered process, a thin layer of oxide containing nitrogen forms at SiO@Sub 2@/Si interface. The gate oxide reliability can be improved in terms of device lifetime. Recently, nitrogen incorporation with nitrogen implantation has been studied. In this paper, ultra-thin gate dielectric was thermally grown on nitrogen implanted silicon substrates. The advantages of this technique are (i) the oxide growth rate can be significantly suppressed and (ii) a multiple gate dielectric thickness on same chip can be realized. However, previous reports showed that gate oxide quality is degraded. In this paper, we demonstrated that higher thermal budget is needed to remove the implantation induced damage and to improve the gate oxide reliability. The gate oxides were either grown or post-oxidation annealed at higher temperature. We also will present that the gate oxide reliability are nitrogen dose dependent. Gate oxide quality was evaluated with three different techniques: current ramp breakdown, time dependent dielectric breakdown and hot carrier aging test. Both current ramp and TDDB indicate that the gate oxide was degraded with nitrogen implant. However, the hot carrier aging test showed that the device lifetimes were longer for the nitrogen implanted ones. CMOS transistors were also fabricated. Device performances such as channel mobility, drive current, device yield will also be reported.