Ge n-MOSFETs on lightly doped substrates with high-/spl kappa/ dielectric and TaN gate

In this letter, we report successful fabrication of germanium n-MOSFETs on lightly doped Ge substrates with a thin HfO/sub 2/ dielectric (equivalent oxide thickness /spl sim/10.8 /spl Aring/) and TaN gate electrode. The highest peak mobility (330 cm/sup 2//V/spl middot/s) and saturated drive current (130 /spl mu/A/sq at V/sub g/--V/sub t/=1.5 V) have been demonstrated for n-channel bulk Ge MOSFETs with an ultrathin dielectric. As compared to Si control devices, 2.5/spl times/ enhancement of peak mobility has been achieved. The poor performance of Ge n-MOSFET devices reported recently and its mechanism have been investigated. Impurity induced structural defects are believed to be responsible for the severe degradation.

[1]  H.-S.P. Wong,et al.  Self-aligned n-channel germanium MOSFETs with a thin Ge oxynitride gate dielectric and tungsten gate , 2004, IEEE Electron Device Letters.

[2]  R. S. Johnson,et al.  New approach for the fabrication of device-quality Ge/GeO2/SiO2 interfaces using low temperature remote plasma processing , 2000 .

[3]  W. Haensch,et al.  High mobility p-channel germanium MOSFETs with a thin Ge oxynitride gate dielectric , 2002, Digest. International Electron Devices Meeting,.

[4]  Fei Gao,et al.  Germanium p- & n-MOSFETs fabricated with novel surface passivation (plasma-PH/sub 3/ and thin AlN) and TaN/HfO/sub 2/ gate stack , 2004, IEDM Technical Digest. IEEE International Electron Devices Meeting, 2004..

[5]  B. Streetman.  Solid state electronic devices , 1972 .

[6]  W. Bai,et al.  Epitaxial strained germanium p-MOSFETs with HfO/sub 2/ gate dielectric and TaN gate electrode , 2003, IEEE International Electron Devices Meeting 2003.

[7]  Ying Zhang,et al.  Selectively formed high mobility strained Ge PMOSFETs for high performance CMOS , 2004, IEDM Technical Digest. IEEE International Electron Devices Meeting, 2004..

[8]  Chi On Chui,et al.  A germanium NMOSFET process integrating metal gate and improved hi-/spl kappa/ dielectrics , 2003, IEEE International Electron Devices Meeting 2003.

[9]  Chenming Hu,et al.  Quantum effect in oxide thickness determination from capacitance measurement , 1999, 1999 Symposium on VLSI Technology. Digest of Technical Papers (IEEE Cat. No.99CH36325).

[10]  R. Chang,et al.  Inversion layers on germanium with low‐temperature‐deposited aluminum‐phosphorus oxide dielectric films , 1986 .

[11]  Y. Kuo,et al.  Stress testing and characterization of high-k dielectric thin films , 2003, IEEE International Integrated Reliability Workshop Final Report, 2003.

[12]  D. Kwong,et al.  3D GOI CMOSFETs with novel IrO/sub 2/(Hf) dual gates and high-k dielectric on 1P6M-0.18 /spl mu/m-CMOS , 2004, IEDM Technical Digest. IEEE International Electron Devices Meeting, 2004..

[13]  T. Tezuka,et al.  Selectively-formed high mobility SiGe-on-Insulator pMOSFETs with Ge-rich strained surface channels using local condensation technique , 2004, Digest of Technical Papers. 2004 Symposium on VLSI Technology, 2004..

[14]  Stefan Kubicek,et al.  Deposition of HfO2 on germanium and the impact of surface pretreatments , 2004 .

[15]  D. Wristers,et al.  Ge MOS characteristics with CVD HfO/sub 2/ gate dielectrics and TaN gate electrode , 2003, 2003 Symposium on VLSI Technology. Digest of Technical Papers (IEEE Cat. No.03CH37407).

[16]  Evgeni P. Gusev,et al.  Microstructure and thermal stability of HfO2 gate dielectric deposited on Ge(100) , 2004 .

[17]  Albert Chin,et al.  Alternative surface passivation on germanium for metal-oxide-semiconductor applications with high-k gate dielectric , 2004 .

[18]  B. Tuck,et al.  Introduction to diffusion in semiconductors , 1975, 1975 First European Solid State Circuits Conference (ESSCIRC).