GaN 기판제작공정 시스넥스기술연구소 박기연
내 용 1. 시스넥스및 HVPE 장비소개 2.GaN 기판제작개요 3. GaN Epi 공정 (HVPE 방법 ) 4. GaN LLO 공정 5. GaN polishing 공정
시스넥스소개 (4-1) 회사연혁및사업분야 2000. 05 회사설립 2001. 05 6x2 GaN MOCVD 개발 ( 국내및중국납품 ) 2004. 11 8x2 HVPE 장비개발 ( 국내 S그룹등납품 ) 2006. 02 6x2 상압 GaN MOCVD 개발 ( 국내 S그룹등납품 ) 2006. 12 3x2 ZnO MOCVD 개발 ( 국내대학납품 ) 2007. 10 자체운영 GaN + ZnO_ 2 Chamber MOCVD 개발 2007. 11 자체운영 HVPE 장비개발완료 시스넥스주력제품 : MOCVD, HVPE, Wafer bonder, Gas cabinet, Gas scrubber
시스넥스소개 (4-2) MOCVD ( 상압, 저압 ) 제품명 : 유기금속화학기상증착기 (Metal Organic Chemical Vapor Deposition) 모델명 : Marvel series ( 6 x 2 ) 용도 : 질화물반도체 (GaN : Gallium Nitride) 박막성장 주요구성 : 반응기 (Reactor), 공정가스공급장치 (Gas Delivery System), 제어부 응용분야 : 청색, 녹색, 백색고휘도 LED 제조핵심공정
시스넥스소개 (4-3) HVPE 제품명 : 수소화합물기상증착기 (Hydride Vapor Phase Epitaxy) 모델명 : Wonder series 용도 : 질화물반도체후막성장 응용분야 : 질화갈륨 (GaN) 기판 (Wafer) 제조 8x2 Two Flow HVPE 1x2 Vertical HVPE 3x2 Horizontal HVPE
시스넥스소개 (4-4) ZnO MOCVD 제품명 : 산화아연유기금속기상증착기 (MOCVD for Zinc Oxide) 모델명 : Zeus series 사용온도 : < 1200 Heating Type : RF 사용 Source : DEZn, Cp2Mg, TEGa, TEP. 사용가스 : O 2, N 2 O, N 2, Ar, H 2.
GaN 기판제작개요 (7-1) 질화물반도체 (GaN) 기술개요 세계 LED & Lamp 시장 -2 Bonding -기판표면처리 -GaN표면처리 조명시장 => 2012년약2천억불시장을형성 LED로광원교체 => 조명시장확대예상 => 미국 2025년조명기구 50 % 대체 * 관련근거 : Global Information. Inc,
GaN 기판제작개요 (7-2) 질화물반도체기판의필요성 Heteroepitaxy No GaN Substrate Homoepitaxy GaN LED Al 2 O 3 GaN LED (5 μm ) Al 2 O 3 GaAs LED GaAs Sub Large Lattice Mismatch Difference in Thermal Expansion Threading Defect Residual Strains 내부 / 외부양자효율특성저하 LED/ LD 특성향상기간지연 Low defect -GaN 기판요구 1. HVPE ( 수소화기상증착법 ) - 성장률이빠르고대용량가능 - 현재가장각광을받고있는방법 Cf. 고온고압법
GaN 기판제작개요 (7-3) GaN 기판제작을위한 HVPE 장치의개략도 HVPE ( Hydride Vapor Phase Epitaxy ) Reaction 2HCl(g) 2HCl(g) + + 2Ga(l) 2Ga(l) 2GaCl(g) 2GaCl(g) + + H 2 (g) 2 (g) GaCl(l) GaCl(l) + + NH NH 3 (g) 3 (g) GaN(s) GaN(s) + + HCl(g) HCl(g) + + H 2 (g) 2 (g) Materials HCl, NH 3, N 2, DCS, Metal Ga, MO-source(available) -. NH 3 : HCl ratio is typically 30 : 1 -. Growth rate typically 100 μm /hr -. Low cost, High growth rate -. Possibility of Expanding to Multi-Wafer Processing
GaN 기판제작개요 (7-4) GaN 기판제작을위한고온고압장치의개략도 HPS( High Pressure Solution ) GaN melting at high nitrogen pressure ( 6 GPa ) high temperature ( 2497 K ) Experimental conditions - high nitrogen pressure ( 2 GPa ) - high temperature ( 2000 K ) Internal diameter : 4, 6, 10 cm Cryst. Res. Technol. 42, No. 12, 1162-1175(2007) XRD FWHM (002) 20 ~ 30 arcsec for 1mm crystal 30 ~ 40 arcsec for 1 3 mm
GaN 기판제작개요 (7-5) TopGaN offers high-quality HVPE GaN crystals. Properties: Transparent and colorless Dislocation density : 10 7 cm -2 XRD rocking curve : 90-100 arcsec Thickness : 0.1-2 mm Surface area up to : 400 mm 2 http://www.topgan.fr.pl/fsgancr.php The resulting surfaces have an RMS surface roughness less than 5 Â with a clearly visible atomic step structure. The resistivity of GaN : Fe is greater than 10^8 ohm-cm at room temperature, as shown in the COREMA resitivity map. http://www.sei.co.jp/sn/2002/07/feature_article.html http://www.cree.com/products/gan_tech.asp
GaN 기판제작개요 (7-6) C-Plane, N-Type Gallium Nitride (GaN) Substrates - 2" rounds, 18x18mm and 10x10mm squares C-Plane, Semi-Insulating Gallium Nitride (GaN) Substrates - 18x18mm and 10x10mm squares Non-polar, N-Type Gallium Nitride (GaN) Substrates - 5x10mm and 7x15mm bars - M-plane [1-100], A-plane [11-20] - Other planes available on request http://www.tdii.com/ganbulk.htm Nothing information of GaN substrate http://www.kymatech.com/products/index.html
GaN 기판제작개요 (7-7) GaN -HVPE grown Single Crystal Substrate (0001), 5 x 5 x 0.3 mm, one side polished (1sp) $398.00 GaN -HVPE grown Single Crystal Substrate (0001), 10 x 10 x 0.32 mm, $1,195.95 one side polished (1sp) http://www.mtixtl.com/index.asp?pageaction=viewprod&prodid=610 Specifications of Substrate Orientation: <0001> +/-0.5 edge : (11-20) Dimension: 10x10 x 0.32 +/-0.05 mm Dislocation density: <5x10 6 / cm 2 Microscpic defect density: < 10 / cm 2 Usable surface area: > 95% Polished: One side epi polished by CMP Roughness: Ra < 10 A Surface Roghness: < 10 A by AFM Conductivity: N type Resistivity: 0.01-0.1 ohm-cm Therer-conductivity: 220 W/ m-k
GaN Epi 공정 (HVPE) (8-1) Sysnex HVPE system 1 Capacity : 1x2 Gas Flow : Vertical Flow type Growth Rate : ~200um/h Source Temp. : Max 800 Growth Temp. : Max 1200 Gas : N 2, HCl, NH 3 [Input Flange] [Wafer Unloading]
GaN Epi 공정 (HVPE) (8-2) Sysnex HVPE system 2 HCl Ga N 2 N 2 NH 3 NH 3 Growth condition Source Temp. : ~ 700 Growth Temp. : ~ 1050 HCl flow : ~ 100 sccm NH 3 flow : ~ 1000 sccm Growth rate : ~ 200 um / hr Rotation speed : ~ 10 rpm GaCl GaN Rotation Vertical HVPE Schematic
GaN Epi 공정 (HVPE) (8-3) HVPE-GaN (~20 um)/mocvd-gan (1 um)/sapphire Microscope SEM X 100 XRD Intensity (arb. units) XRD Intensity (arb. units) XRD (002) -1500-1000 -500 0 500 1000 1500 Angle (arcsec) FWHM 339 arcsec (102) -1500-1000 -500 0 500 1000 1500 Angle (arcsec) FWHM 365 arcsec
GaN Epi 공정 (HVPE) (8-4) HVPE-GaN ( 20 um )/Sapphire Microscope X 500 SEM XRD Intensity (arb. units) XRD Intensity (arb. units) XRD -1500-1000 -500 0 500 1000 1500 Angle (arcsec) FWHM 406 arcsec FWHM 375 arcsec (002) (102) -1500-1000 -500 0 500 1000 1500 Angle (arcsec)
GaN Epi 공정 (HVPE) (8-5) MOCVD-GaN ( 2 um )/HVPE-GaN ( 10 um)/sapphire Microscope X 100 X 500 SEM HVPE GaN 위에 MOCVD GaN 성장시 Crack 발생 * Crack 방지를위한최적화필요
GaN Epi 공정 (HVPE) (8-6) 후막 GaN 성장 ( 보고자료 ) GaN GaN * S 사 data GaN GaN intermediate layer sapphire sapphire Crack free Thick GaN 성장을위한 Key points GaN 와 sapphire 사이의 stress 완화층성장필요 표면처리, Bowing 최소화필요 ( Epi crack, LLO 적용시 crack 발생줄임 )
GaN Epi 공정 (HVPE) (8-7) 후막 GaN 성장방향 1 ( 시스넥스 HVPE ) Growth condition Microscope Source Temp. : ~ 700 Growth Temp. : 950 ~ 1050 HCl flow : ~ 100 sccm NH 3 flow : ~ 1000 sccm X 100 Growth rate : ~ 150 um / hr Rotation speed : ~ 10 rpm Thick GaN ( ~ 300 um ) - unloading speed : 5 rpm / ~ 90 min - run to run growth time : 8 hr Intermediate layer Intermediate layer -Low Temp
GaN Epi 공정 (HVPE) (7-7) GaN / Sapphire Bowing (1) (2) 에서의 bowing 측정 532 533 545 530 535 두께편차 : 15 um 633 sapphire GaN GaN sapphire Deflection ( um ) 1000 800 600 400 200 Crack free GaN(100um)/sapphire(430um) 680 1260 667 744 0 0 10 20 30 40 50 Length ( mm ) Bowing 최소화필요 ( Epi crack, LLO 적용시 crack 발생줄임 )
GaN LLO 공정 (HVPE) (1-1) Laser Lift off process Laser Lift off : 355nm Nd-YAG laser ( ~ 780mJ/cm 2 ) Operation laser power : ~ 450 mj/cm 2 Problems ( During the laser lift -off ) Crack free 400 μm GaN / Sapphire => Wafer broken Wafer : temp. up to the ~ 800 => Wafer broken 355nm Nd-YAG laser laser lift -off and wafer bonding Bonding materials Epoxy, In-Pd, SeS2, BCB, ethyl cyanoacrylate(c6h7no2) Thin film GaN LED (backside) Thin film GaN (backside) Thick GaN
GaN polishing (2-2) Polished GaN Microscope Polished freestanding GaN AFM Polished freestanding GaN X 100 RMS : 3 A TEM image Before ICP ( ~ 3000A ) Before ICP ( ~ 3000A ) After ICP ( ~ 3000A ) ~ 2000A Polished freestanding GaN