We have integrate HfO2 and Al2O3 gate dielectrics grown by atomic layer chemical vapor deposition (ALD) with poly-Si gate electrodes in the vertical replacement-gate (VRG) MOSFET geometry (1,2). The transistors are among the first reported with ALD HfO2 gate dielectrics, and have HfO2 target equivalent oxide thickness (tEOTs) down to 13 Å. The poly-crystalline HfO2 films in these VRG nMOSFETs exhibit extremely low gate leakage (GL) current densities of JG ∼ 10-7 A/cm2 at VG-VT,Long = 0.6 V for 15 Å tEOT devices. This indicates that amorphous gate dielectrics may not be necessary to meet GL requirements. HfO2 devices with 50 nm gate length LG exhibit drive currents [normalized by the coded width WC (1)] of 490 μA/μm for 1 V operation (overdrive VGS-VT = 0.6 V) with good short-channel performance. These results demonstrate that ALD is compatible with the demanding VRG geometry, thereby illustrating that it should be well-suited to essentially any novel device structure built with Si-compatible materials.
|Original language||English (US)|
|Number of pages||4|
|Journal||Technical Digest - International Electron Devices Meeting|
|State||Published - Dec 1 2001|
|Event||IEEE International Electron Devices Meeting IEDM 2001 - Washington, DC, United States|
Duration: Dec 2 2001 → Dec 5 2001