Title :
New insight into Fermi-level unpinning on GaAs: Impact of different surface orientations
Author :
Xu, M. ; Xu, K. ; Contreras, R. ; Milojevic, M. ; Shen, T. ; Koybasi, O. ; Wu, Y.Q. ; Wallace, R.M. ; Ye, P.D.
Author_Institution :
Sch. of Electr. & Comput. Eng., Purdue Univ., West Lafayette, IN, USA
Abstract :
We have systematically studied NMOSFETs, MOSCAPs, and the interfacial chemistry on GaAs (100), (110), (111)A and (111)B-four different crystalline surfaces with direct ALD Al2O3. We found that a much higher drain current on GaAs(111)A NMOSFET can be achieved compared to that obtained on the other 3 surfaces. Also, the results of MOS-CAPs and the interfacial chemistry obtained on the (111)A surface are very different from those others. These experimental results conclusively demonstrate that Fermi-level on the GaAs (111)A surface is indeed unpinned and Fermi-level pinning is not an intrinsic property of GaAs, but is orientation dependent thus related to surface chemistry.
Keywords :
Fermi level; III-V semiconductors; MOSFET; gallium arsenide; surface chemistry; wide band gap semiconductors; (lll)A NMOSFET; GaAs; MOSCAP; crystalline surfaces; direct ALD; drain current; fermi-level unpinning; interfacial chemistry; surface chemistry; surface orientations; Aluminum oxide; Chemistry; Crystallization; Dielectric substrates; Frequency; Gallium arsenide; High-K gate dielectrics; Intrusion detection; MOSFET circuits; Photonic band gap;
Conference_Titel :
Electron Devices Meeting (IEDM), 2009 IEEE International
Conference_Location :
Baltimore, MD
Print_ISBN :
978-1-4244-5639-0
Electronic_ISBN :
978-1-4244-5640-6
DOI :
10.1109/IEDM.2009.5424269
