DocumentCode :
834466
Title :
Implementation of fully self-aligned bottom-gate MOS transistor
Author :
Shengdong Zhang ; Ruqi Han ; Zhikuan Zhang ; Ru Huang ; Ko, P.K. ; Mansun Chan
Author_Institution :
Dept. of Electr. & Electron. Eng., Hong Kong Univ. of Sci. & Technol., China
Volume :
23
Issue :
10
fYear :
2002
Firstpage :
618
Lastpage :
620
Abstract :
This letter reports the implementation of a bottom-gate MOSFET, which possesses the following fully self-aligned structural features: 1) self-aligned source-drain to bottom-gate; 2) self-aligned thick source-drain and thin channel; and 3) self-aligned and mask-free lightly doped drain (LDD). The complete self-alignment is realized by combining a conventional ion implantation and a subsequent chemical-mechanical polishing (CMP) step. The process is applied to poly-Si films crystallized from an a-Si film deposited by LPCVD using a metal-induced unilateral crystallization technique, and is grain-enhanced further in a high temperature annealing step. Deep submicron fully self-aligned bottom-gate pMOS transistors with channel length less than 0.5 μm are fabricated. The measured performance parameters include threshold voltage of -0.43 V, subthreshold swing of 113 mV/dec, effective hole mobility of 147 cm2/V-s, off-current of 0.17 pA/μm, and on-off current ratio of 7.1×10/sup 8/.
Keywords :
MOSFET; chemical mechanical polishing; hole mobility; ion implantation; recrystallisation annealing; semiconductor device measurement; -0.43 V; 0.5 micron; LPCVD; SRAM; channel length; chemical-mechanical polishing step; deep submicron fully self-aligned bottom-gate pMOS transistors; effective hole mobility; fully self-aligned bottom-gate MOSFET; grain enhancement; high temperature annealing; ion implantation; mask-free lightly doped drain; metal-induced unilateral crystallization; off-current; on-off current ratio; poly-Si film; self-aligned source-drain; self-aligned thick source-drain channel; self-aligned thin channel; subthreshold swing; threshold voltage; Annealing; Chemical vapor deposition; Crystallization; Current measurement; Fabrication; Ion implantation; MOSFET circuits; Random access memory; Temperature; Thin film transistors;
fLanguage :
English
Journal_Title :
Electron Device Letters, IEEE
Publisher :
ieee
ISSN :
0741-3106
Type :
jour
DOI :
10.1109/LED.2002.803763
Filename :
1039186
Link To Document :
بازگشت