서지주요정보
차세대 디램 스토리지 노드를 위한 원자층 증착 공법 산화 하프늄지르코늄 커패시터 = Next-generation DRAM storage node with atomic layer deposition $Hf_xZr$yO_2$ capacitor
서명 / 저자 차세대 디램 스토리지 노드를 위한 원자층 증착 공법 산화 하프늄지르코늄 커패시터 = Next-generation DRAM storage node with atomic layer deposition $Hf_xZr$yO_2$ capacitor / 이승환.
발행사항 [대전 : 한국과학기술원, 2020].
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8036083

소장위치/청구기호

학술문화관(문화관)B1층 보존서고

MEE 20069

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$HfZrO_2$ appears to be a promising alternative to $ZrO_2$/$Al_2O_3$/$ZrO_2$, the dielectric layers of DRAM cell capacitors that are currently reaching their limits. However, the reported $HfZrO_2$ capacitors are not suitable for current DRAM cell capacitors. Therefore, In this thesis, $HfZrO_2$ capacitors were fabricated with whole ALD process to evaluate their performance. In addition, for the next generation of DRAM cell capacitors, $HfZrO_2$ capacitors using WN electrodes that can replace current TiN electrodes are implemented to suggest directions for DRAM cell capacitors.

현재 한계를 맞이한 DRAM 셀 커패시터의 유전층인 $ZrO_2$/$Al_2O_3$/$ZrO_2$를 대체할 물질로 $HfZrO_2$가 유력해 보인다. 하지만, 현재까지 보고된 $HfZrO_2$ 커패시터는 그 공정 방식이 현재 DRAM 셀 커패시터에는 적합하지 않다. 이에 본 학위논문에서는 전 공정이 ALD로 구성된 $HfZrO_2$ 커패시터를 제작하여 그 성능을 평가했다. 추가로, 차세대 DRAM 셀 커패시터를 위해, 현재 사용하고 있는 TiN 전극을 대체할 수 있는 WN 전극을 도입한 $HfZrO_2$ 커패시터를 구현하여 DRAM 셀 커패시터가 나아갈 방향성을 제시하고자 한다.

서지기타정보

서지기타정보
청구기호 {MEE 20069
형태사항 ix, 34 p. : 삽화 ; 30 cm
언어 한국어
일반주기 저자명의 영문표기 : Seung-Hwan Lee
지도교수의 한글표기 : 조병진
지도교수의 영문표기 : Byung-Jin Cho
학위논문 학위논문(석사) - 한국과학기술원 : 전기및전자공학부,
서지주기 참고문헌 : p. 31-33
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이 주제의 인기대출도서

DRAM in memory hierarchy and supply and demand trend [Gartner]

1T-1C scheme DRAM cell structure (a) schematic diagram [1] (b) circuit diagram (c) TEM cross section image [chip works]

(a) History of DRAM cell capacitor and (b) k-value (Cs) leakage current of Zr02 with interlayer [ITRS 2001~2015] [IRDS 2017] [7-8]

(a) Aspect ratio(A/R) trend of cell capacitor (b) cell capacitance(C.) trend [8]

(a) Dead layer problem of TiN electrode with Ti02 capacitor[10, 11] (b) Ti02 base capacitor with Ru electrode (c) Physical thickness VS. EOT[11] (d) leakage current VS. EOT of Ti02 base capacitor[11]

(a) P-V, C-V characteristics of Hf.Zry02 with various composition [16] (b) Schematic of polarization in Hf,Zry02 [17]

(a) Hf02 in GAAFET [18] (b) TiN electrode in Hf,Zry02 capacitor [19] (c) increasing k-value of Hf,Zry02 with thin film thickness [20]

Phase of Hf.Zry02 with smaller grain size [21]

(a) Wide process window of Zr in HfO2 [22] and ALD super cycle of (b) ZAZ structure (c) HfZr02 structure

Usage of atomic layer deposition in DRAM industry [4, 23]

(a) ALD reaction chamber (b) ALD reaction mechanism [24]

Process Window increase with Plasma energy [25]

Comparisons of ALD, CVD and PVD

(a) Reported Hf.Zry02 with PVD TiN electrode [20, 26-29] (b) Schematics of PVD, CVD and ALD at deep trench structure

Process flow of (a) cylinder and (b) pillar type capacitor schematic diagram of (c) cylinder type and pillar type structure and (d) unit capacitor

Key process steps and details for the fabrication of MIM structure ALD HfZr02 capacitors

SIMS profiles of Hf, Zr, Si, c, N and 0 in the thin film ALD Hf,Zry02

(a) GIXRD patterns of PVD TiN and ALD TiN (b) schematic diagram of XRD sample (c) asymmetric stress of ALD TiN on HfZr02 crystallization

Effective work function of ALD TiN (a) Schematic of MOS capacitor stack (b) capacitance-voltage graph (c) flat-band voltage VS. CET graph

(a) Refractive index and extinction coefficient of HfZr02 (1:3) in ellipsometer (b) Optical thickness of HfZr02 films with various compositions

(a) CS-TEM cross section image of ALD HfZr02(1:3) capacitor (b) Physical thickness of ALD HfZr02 film with various composition

SIMS profiles of Hf, Zr, Si, C, N and 0 in the thin film ALD Hf,Zry02

GIXRD patterns of ALD HfZr02 thin films with various composition

CS-TEM cross section image of ALD HfZr02 capacitors with various composition

(a) Dielectric constant-voltage curves and dielectric constant at Vg = 0 of ALD Hf.Zry02 capacitor with various composition and annealing temperature (b) schematic diagram of ALD Hf,Zry02 capacitor and dielectric constant at (c) 3.0 V forward (d) 1.0 V forward (e) 3.0 V reverse (f) 1.0 V reverse sweep

(a) Capacitance-gate voltage and (b) polarization-gate voltage of ALD Hf,Zry02 capacitor(1:3) with various annealing temperature(as-dep, 400'C, 500'C, 600'C, 700'C, 800'C)

Dielectric constant at Vg - 0 and EOT trend of ALD Hf.Zry02 capacitor(1:3) with various annealing temperature at (a) 士1.0V sweep (b) 土3.0 V sweep

(a) Leakage current-gate voltage and (b) voltage at Jg-1.0 nA/cm2 trend of ALD Hf,Zry02 capacitor(1:3) with various annealing temperature(as-dep, 400'C, 500'C, 600'C, 700'C, 800'C)

Root causes of leakage current in MIM structure (a) interlayer formation (b) grain boundary leakage path (c) trap site leakage path (d) band structure

(a) Capacitance-gate voltage and (b) polarization-gate voltage of ALD Hf,Zry02 capacitor(1:1) with various annealing temperature(as-dep, 400'C, 500'C, 600'C, 700'C, 800'C)

Dielectric constant at Vg - 0 and EOT trend of ALD Hf.Zry02 capacitor(1:1) with various annealing temperature at (a) 士1.0V sweep (b) 士3.0V sweep

(a) Leakage current-gate voltage and (b) voltage at Jg-1.0 uA/cm2 trend of ALD Hf.Zry02 capacitor(1:1) with various annealing temperature(as-dep, 400'C, 500'C, 600'C, 700'C, 800C

Comparison of ALD HfZr02 (1:1) and (1:3) with various annealing temperature (a) dielectric constant (b) polarization (c) leakage current (d) endurance [28]

TEM cross section image of (a) DRAM cell capacitor [chip works] (b) TiN in deep trench [32]

(a) TEM cross section image of WN in deep trench [34] and comparisons of metal nitride (b) density [33] (c) resistivity [34-37]

Key process steps and details for the fabrication of WN electrode for Hf,Zry02 capacitors

(a) GIXRD patterns of WN with various annealing temperature(as-dep, 600'C, 800'C)

(a) Hf/Zr ratio with HfO2 target power in co-sputtering (b) maximum polarization and remnant polarization with various Hf/Zr ratio

(a) P-V characteristic, (b) polarization window and (Pmax+ - Pmax-)/(P<+ -Pr-) of Hf.Zry02 with various annealing temperature (700'C, 800'C, 900'C)

(a) AFM image of HfZr02 (b) schematic diagram of Hf.Zry02 AFM sample

(a) C-V curve of Hf,Zry02 capacitor with TiN and WN electrode and (b) their k-value trend

(a) P-V curve of HfxZry02 capacitor with TiN and WN electrode and (b) their Pmax trend

(a) I-V curve of Hf,Zry02 capacitor with TiN and WN electrode and (b) their leakage current trend

k-value of reported Hf.Zry02 capacitor with PVD TiN electrode and this work [20, 26-29]