櫶櫶櫶櫶櫶櫶櫶櫶櫶櫶櫶櫶櫶櫶櫶櫶櫶櫶櫶櫶櫶櫶櫶櫶櫶櫶櫶櫶櫶櫶櫶櫶櫶櫶櫶櫶櫶櫶 DOI 10. 13290 /j. cnki. bdtjs. 2014. 02. 006 Ge /SiGe 361005 HfO 2 k Si Ge /SiGe SB- n Si 0. 16 Ge 0. 84 n SiGe UHV CVD Ge Si Ge 32 nm Si 0. 16 Ge 0. 84 12 nm Ge 1 nm Si X Ni NiGe /Ge p Ge /SiGe 1. 5 80% Ge /SiGe TN386 A 1003-353X 2014 02-0108 - 06 Schottky Barrier S / D Metal Oxide Semiconductor Field Effect Transistors with Ge / SiGe Heterostructure Zhang Maotian Liu Guanzhou Li Cheng Wang Chen Huang Wei Lai Hongkai Chen Songyan Department of Physics Semiconductor Photonics Research Center Xiamen University Xiamen 361005 China Abstract Si-based Ge /SiGe heterostructure Schottky barrier source and drain metal oxide semiconductor field effect transistors SB-s with hafnium dioxide high-k gate were fabricated. The effect of the n-type doped Si 0. 16 Ge 0. 84 layer on the device performance was investigated and the mechanism of the device off-state current reduction caused by the n type doping SiGe layer was analyzed. Firstly Ge buffer was fabricated with low-temperature Ge buffer technique. Then a 32 nm Si 0. 16 Ge 0. 84 layer and a 12 nm Ge layer were grown on the Ge buffer in the same UHVCVD system. For comparative study the 32 nm Si 0. 16 Ge 0. 84 layer was controlled undoped or n-type doped by P. For all samples 1 nm Si layer was grown to passivate the Ge surface. Atomic force microscopy and X-ray diffraction were used to characterize the surface morphology and crystal quality of the materials. NiGe / Ge Schottky junctions in source and drain were formed by nickel layer deposition and anneal. The fabricated Ge / SiGe heterosturctual device without n-type doping shows 150% enhancement of the hole effective mobility over that of the control Si device and about 80% enhancement over the universal Si device. And the device with n-type doping shows a comparable hole effective mobility with the universal Si device. Key words Ge /SiGe heterosturcture Schottky barrier off-state current mobility doping EEACC 2560R 61036003 61176092 973 2012CB933503 2013CB632103 2010121056 E-mail lich@ xmu. edu. cn 108 39 2 2014 2
Ge /SiGe 0 80% n SiGe 1 III-V Ge Ge UHVCVD Si Ge Si Si 2 4 Si 440 nm Ge 32 nmsige 12 nm Ge 1 nm Si 4 1 = Si Ge 2. 54 cm n Si 100 0. 1 ~ 1. 2 Ω cm RCA n Ge 200 1 h 10-8 Pa 900 30 min k 750 Ge 300 nm Si 330 90 nm Ge k 600 350 nm Ge Ge 2002 H. Shang 1 11 Ge /SiGe GeON Ge 20 nm SiGe 10 nm P Si SiGe Ge Si A P B 2 nm SiGe 2 3 - GeO 2 4 NH 4 2 S 5 H 2 S 6 600 12 nm Ge Ge k Ge 380 1 nm Si P SiGe Ge Ge 5 10 17 cm - 3 Ge Ge SB- 2010 R. Pillarisetty 7 Ge 20 nm HfO 2 20 nm TaN 770 cm 2 V - 1 s - 1 2012 HfO 2 /TaN k / P. Hashemi 8 Ge 10 nm Ni 400 60 s 940 cm 2 V - 1 s - 1 NiGe /Ge Ni k Ge 200 240 μm 1 2007 T. Yamamoto 9 SiO 2 NiGe /Ge Ge 250 cm 2 / V s 2012 B. Liu 10 Ge 10 2 FET 740 μs /μm k / Si 1 Ge /SiGe SB- Ge /SiGe NiGe /Ge Fig. 1 Structure schematic of the SB- with Ge / SiGe p Ge MOS- heterostructure February 2014 Semiconductor Technology Vol. 39 No. 2 109
Ge /SiGe 2 Ge 0. 84 B SiGe Ge 0. 87 Ge A B Ge 0. 19% 0. 12% 2. 1 B P Si secondary ion mass spectroscopy SIMS 2 4 4 d x A SiGe Si Ge N D SiGe 0. 4 nm B 0. 7 nm 2 Fig. 2 3 X XRD SiGe Si SiGe Ge Ge SiGe P Ge P A Ge 630! 30 nmsige Ge P SiGe 820! B Ge SiGe SIMS SiGe XRD 750! 1 000! XRD 2. 2 XRD A B SiGe Ge Ge A SiGe 3 Fig. 3 A B Ge /SiGe XRD XRD curves of Ge / SiGe heterostructure materials of sample A and sample B 4 B P SIMS Fig. 4 Secondary ion mass spectroscopy SIMS profiles of phosphorus in sample B 4 Ge Si P SiGe AFM images of samples' morphology N D 5 10 17 cm - 3 P A B 0 V - 3 V - 0. 5 V 5 A B I DS -V DS I DS V DS V GS A 0 V B - 1 V A Ge p NiGe p-ge B n A A 110 39 2 2014 2
Ge /SiGe B NiGe /Ge - 1 V Ge 7 A B I DS -V GS 1 V - 3 V - 0. 1 V A B A B B P 5 A B I DS -V DS B Fig. 5 I DS -V DS characteristic curves of sample A and A sample B A Ge I-V p NiGe /Ge NiGe /Ge J-V B 6 NiGe /Ge B n SiGe B J TE [ ( ) ] ( ) exp qv kt - 1 1 J TE = A * T 2 exp - q Bn kt A * k T Bn J s m J m s I-V B NiGe /Ge 0. 63 ev 6 A B J-V Fig. 6 J-V characteristic curves of the Schottky source / drain junctions of sample A and B A I-V NiGe p-ge B 7 A B Fig. 7 I DS -V GS characteristic curves of samples A and sample B SiGe Ge P n-ge NiGe /Ge 12 NiGe /Ge 13 177-179 J n = J s m + J m s = A * T 2 exp - q Bn [ ( ) ] kt [ ( ) ] exp qv kt - 1 = V DS 50 ~ 100 mv I DS February 2014 Semiconductor Technology Vol. 39 No. 2 111
Ge /SiGe I DS = k( V GS - V T - 0. 5V ) ( DS V DS - I DS R ) 2 SD R SD I DS = 0 V GS - V T - 0. 5V DS = 0 I DS = 0 V GS = V GSi Si 80% E eff = 0. 1 MV cm - 1 V T = V GSi - 0. 5V DS 313 cm 2 V - 1 s - 1 Si V T I DS -V GS 150% B P V T B I DS -V GS A I DS -V GS Si g m = I DS / V GS I DS -V GS I DS = 0 8 B V T = - 0. 94 V A - 0. 2 V B SB- Si 90% A 9 Fig. 9 A B Dependence of the effective hole mobility on the effective field of sample A and sample B 8 313 cm 2 / V s Si Fig. 8 Schematic diagram of the method for measuring the linear threshold voltage 80% Si 150% n 13 397 - SiGe NiGe /Ge 401 V DS 50 ~ 100 mv Ge p μ eff p E eff P μ eff = g dl 3 Q n W E eff = Q b + Q n /3 ε s ε 0 4 3 Ge /SiGe Ge /SiGe g d = I DS V DS V GS = const 1 SHANG H OKOM-SCHMIDT H CHAN K K et al. Q n = C ox ( V GS - V ) High mobility p-channel germanium s with a thin T Q b = 4κ s ε 0 ktn A ln N Ge oxynitride gate dielectric C Proceedings of IEEE A 槡 ( n ) ε s International Electron Devices Meeting. San Francisco i USA 2002 441-444. ε 0 L /W 2 MITARD J VICENT B JAEGER B D et al. Electrical characterization of Ge-pFETs with HfO 2 /TiN metal 3 4 9 Si gate review of possible defects impacting the hole 112 39 2 2014 2
Ge /SiGe mobility J. ECS Trans 2010 28 2 157-169. 3 DELABIE A BELLENGER F HOUSSA M et al. Effective electrical passivation of Ge 100 for high-k gate dielectric layers using germanium oxide J. Applied Physics Letters 2007 91 8 082904-1 -082904-3. 4 TORIUMI A TABATA T LEE C H et al. Opportunities and challenges for Ge CMOS Control of interfacing field on Ge is a key J. Microelectronic Engineering 2009 86 7 /8 /9 1571-1576. 5 SIONCKE S LIN H C BRAMMERTZ G et al. Atomic layer deposition of high-k dielectrics on sulphur passivated germanium J. Electrochemic Soc 2011 158 7 687-692. 6 MERCKLING C CHANG Y C LU C Y et al. J. Micro- molecular beam passivation of Ge 001 electron Eng 2011 88 399-402. H 2 S 7 PILLARISETTY R CHU-KUNG B CORCORAN S et al. High mobility strained germanium quantum well field effect transistor as the p-channel device option for low power V cc = 0. 5 V III-V CMOS architecture C Proceedings of 2010 IEEE International Electron Devices Meeting. San Francisco USA 2010 150-153. 8 HASHEMI P HOYT J L. High hole-mobility strained- Ge /Si 0. 6 Ge 0. 4 p-s with high-k /metal gate role of strained-si cap thickness J. IEEE Electron Device Lett 2012 33 2 173-175. 9 YAMAMOTO T YAMASHITA Y HARADA M et al. High performance 60 nm gate length germanium p-s with Ni germanide metal source /drain C Proceedings of IEEE International Electron Devices Meeting. Washington DC USA 2007 1041-1043. 10 LIU B GONG X HAN G Q et al. High-performance germanium Ω-gate MuGFET with Schottky-barrier nickel germanide source / drain and low-temperature disilane-passivated gate stack J. IEEE Electron Device Lett 2012 33 10 1336-1338. 11. UHV /CVD J. 2012 61 7 078104. 12. M. 2008 118-120. 13. M.. 2008. 2013-10 - 30 1989 1970 Si 650 V 2014 1 9 FSL306 FSL336 650 V AC 250 μa FSL306 0. 5 ~ 3 W FSL306 FSL336 650 ms PWM FSL306 FSL336 February 2014 Semiconductor Technology Vol. 39 No. 2 113