光MEMS
東北大学大学院工学研究科ファインメカニクス専攻
羽根 一博
MEMS集中講義 8月1日(火) 10:40-12:00
内容
1.はじめに 国際会議等の傾向など
2.ディスプレイ
3.車載用スキャナ
4.高機能ミラー
5.光通信とシリコンフォトニクス
6.ミラーとLSIの集積
7.異種半導体の集積(Si+GaN)
8.まとめ
Transducers 2017
Transducers 2017
Tele
com
Scanning mirror,
Imaging
Sensor,
Sensing
Optical
components,
Actuator,
Integration
Bio
Medical
Others
Meta
material
20179%
7%
10%
10%
11%10%9%
19%
15%
Telecom 12 Scanning Mirror, Imaging 9
Sensor and Sensing 13 Optical components, Actuator 13
Bio 14 Adaptive Opt. 13
Nano Opt. 12 Meta material 25
Others 19 Total 130
Opt MEMS 2016
Opt MEMS 2016
ディスプレイ
マイクロミラーディスプレイ
走査
走査
DMD型
GLV型
MS型
投影光学系
2次元ミラーアレイ 白色インコヒーレント(2次元空間変調器)
1次元ミラーアレイ 三原色レーザ(1次元空間変調器+1次元走査)
2次元走査単一ミラー 三原色レーザ(2次元走査)
http://www.dlp.com/jp/pico-projector/phone-projector/default.aspx
DLP Pico プロジェクタ5~50 インチの画像表示内蔵デジタルカメラLED 光源高解像度のカラータッチスクリーン直感的なフリック・ナビゲーションでプレゼンテーションやスライドショーを操作内蔵オーディオスピーカ完璧なモバイルオフィスおよびエンターテインメント・ソリューション軽量かつコンパクトなデザインDLP Pico チップセット
Laser Focus World January 2011 p9
http://goodereader.com/blog/e-paper/qualcomm-
mirasol-screen-technology-what-went-wrong
明るい場所で比較した液晶とMEMS
シャッター
朝日新聞ニュース2014
応用物理 76(2007)174
Optical MEMS 2009
2D micromirror scanner
Light source 3 color LDs
Scanning三原色レーザ
2軸走査マイクロミラー
ビーム走査
スクリーン
2次元走査レーザディスプレイ
レーザディスプレイへの要求仕様
1.1
DN
θ:光学角(rad)
解像度N:
D:ミラー直径(m)
λ:波長(m)
17
Optical MEMS 2008
2015;米ソニーからモバイルプロジェクターMP-CL1の発売が開始された。価格は350ドル。Wi-FiやHDMI/MHL接続ができ、スマートフォンやタブレットの映像を投影可能だ。ソニーは昨年初めに、同社のイメージセンサーとMicroVisionのMEMS(微小電気機械システム)ミラー技術を応用したPicoPモジュールを開発している。独自開発のレーザー走査方式(LBS)技術によって、投影面との距離や角
度にかかわらず焦点を合わせることができる「フォーカスフリー」が特長。また斜め画像歪補正回路により、投影面に対して斜めから投影すると台形などに歪む映像も本来の長方形画面に補正できるとしている。レンズは固定焦点レンズ。ネイティブ解像度はバッテリー駆動のピコプロジェクターで主流のVGAやWVGAを上回るHD解像度(1920×720)を実現。アスペクト比は16:9で、コントラスト比は80000:1。3メートルの距離で約120インチのスクリーン投影ができる。
HD解像度(1920×720)を実現http://www.pronews.jp/news/20151020185038.html
走査ミラーの市販モバイルプロジェクター
共振スキャナーのモデル
)exp(02
2
tikdt
dC
dt
dI
蓄えられるエネルギー(1周期)
20
20
2
1IE
消費されるエネルギー(1周期)
200 CL
C
I
L
EQ 02
共振運転: 消費エネルギー=電気的供給エネルギー
R
VCL
2200
RC
V
0
0
I
k 0)0( C
R: 電気等価抵抗
θ:機械角(rad)
0
500
1000
1500
2000
2500
3000
0 2 4 6 8 10 12 14 16
Mirror in air
Fracture limit
Mirror in vacuum
Resonant scanning frequency f0 (kHz)
Re
so
lutio
n n
um
be
r N
D=1.4mm
1.5
2.0
2.53.0
3.51.2 1.1 1.0
1.51.4
2.5
D=3.0mm
G=6.15×1010Pa (Siヤング率:160GPa、ポアソン比:0.3)、 λ=0.7μm、 a=20μm、 ℓ=150μm、 ρ=2.3×103Kg/m3、Ω=8733、 h=10μm、 g=150μm、 μ=1.8×10-5Pa・sec(大気圧)
共振スキャナーのモデル解析
陽極接合による2Dミラーのパッケージ
H.M.Chu etal, J. Electrostatics 71(2)(2013)130-133
500 μm
スキャンイメージ
ミラー共振周波数:40kHz
フレーム共振周波数:162Hz
水平方向回転軸垂直方向回転軸
ミラー電圧:12V(11.5度)
フレーム電圧:10V(14度)
圧力:1Pa 真空
2軸回転の走査マイクロミラー
低融点金属の支持構造を用いた陽極接合
1.高真空ベーキングによる排気2.ゲッターの活性化3.真空中接合
パッケージした2Dマイクロミラー
H.M.Chu, T.Sasaki, K.Hane, Transducers’11 558-561
100
101
102
3000
3600
4200
4800
5400
6000
6600
7200
7800
8400(b)Packaged mirror (Type I)
Qual
ity F
acto
r
Pressure (Pa)
100
101
102
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
7.5
8.0
(a)Packaged mirror (Type I)
Opti
cal
Rota
tion A
ngle
(deg
rees
)
Pressure (Pa)
振動振幅とQ値の圧力依存性
パッケージ内圧力:0.7Pa
High-Q MEMS Resonators for Laser Beam Scanning DisplaysU. Hofmann, J. Janes H-J.Quenzer, Micromachines 2012, 3, 509-528
High Q-factors up to 145,000 total optical scan angle of 86 degrees at a resonant frequency of 30.8 kHz
車載用スキャナ
棚橋ら,「レーザープロジェクターを用いたフルカラーヘッドアップディスプレイの開発」,PIONEER R&D (Vol.22, 2013),1-7
レーザープロジェクターを用いた`ヘッドアップディスプレイ(パイオニア)
ラスタースキャン方式
レーザープロジェクターの外観写真
RGB 光源モジュールの外観写真
パイオニア(株),光学43(10)464(2014)
今夏、Googleの開発した自動運転専用車もいよいよ公道デビュー
http://www.atmarkit.co.jp/ait/articles/1505/29/news024.html
赤外線レーザ
赤外線検出器
Time of fright 測定
用途 走査角度 分解能 周波数 最小ミラー径(投光)
距離検出投光用 90~360度
~0.5度/点150点~600点
>200Hz
~110μm
運転支援ディスプレイ >30度
>0.05度/点640点(VGA)
16kHz
(VGA) ~670μm
車載用MEMSスキャナの仕様例
日経エレクトロニクス 2016年1月号 Emerging TechMEMS技術で3次元LIDARが小型化、パイオニアや日本信号が相次ぎ投入日経Robotics、今月の1本 進藤智則 2015/12/18 00:00 1/3ページ
市販LIDAR
受光用7x2
スキャナ投光用スキャナ
T. Sandner, et.al. Proc. SPIE 7594, doi: 10.1117/12.844926 (2010)
Omnidriectional scanning concept
Schematic cross-section of the packaged MEMS mirror
Fabricated tripod MEMS mirror
Circular scanning trajectory by biaxial MEMS actuation
The MEMS mirror oscillates at 550 Hz.
mirror diameter = 7 mm
circular scan trajectory
mechanical tilt angle = +/-
15 degrees
a high Q-factor in vacuum
encapsulation
Optical MEMS 2012 pp. 150-151
詳細:J. Micro/Nanolith. MEMS MOEMS 13(1), 011103 (Jan–Mar 2014)
全方向走査マイクロミラー
1000mmContact hole
Frame
Mirror
Comb Electrode
Scanning beam pattern
2.5 deg.
2.5
de
g.
Size [mm]
Mirror Area 3480 * 2000
Torsion Bar Length 425
Torsion Bar Width 20
Device Layer Thickness 50
Handle Layer Thickness 200
高機能ミラー
焦点可変ミラー付きスキャナ
Varifocal Scanner Using Wafer Bonding
K. Nakazawa, et.al, J. MEMS 26(2) (2017) 440-447
Varifocal
mirror
Movable
comb
Torsion
spring
Electrode of
Fixed comb
Electrode of
varifocal mirror
Varifocal mirror Scanner
Diameter 2 mm Torsion bar length 770 μm
Thickness 10 μm Torsion bar width 60 μm
gap spacing 25 μm Torsion bar thickness 60 μm
Number of beams 16 Number of combs 21
Comb length 500 μm
Comb width 30 μm
Comb gap spacing 10 μm
Design parameters of the varifocal scanner
Au – Au thermocompression
bonding
high yield, high electrical
conductivity, low process
temperature
Fabrication Scanner chip
Si SiO2
Scanner chip
SOI wafer (60 μm/2 μm/300 μm)
1. SiO2 deposition, pattering 3. Si etching 5. BOX etching
2. Cr/Au deposition, pattering 4. Si etching
Bonding pad
(frame)Bonding pad
(mirror)
Torsion
spring
Electrode of
fixed comb
1 mm
Electrode of
mirror
Fabricated Scanner Chip
Cr/Au
Counter
electrode
Fabrication Mirror chip
Si SiO2 Cr/Au
3. Cr/Au deposition, pattering1. SiO2 deposition, pattering
Bonding pad
(frame)Bonding pad
(mirror)
1 mm
2. Si etchingMirror chip
SOI wafer (10 μm/2 μm/300 μm)
Varifocal
mirror
Fabricated Varifocal Mirror Chip
Si SiO2 Cr/Au
1. Bonding 2. Si etching
1 mm
Varifocal
mirror
Fixed comb
3. BOX etching
Fabricated Varifocal Scanner
Fabrication Bonding and Releasing
Process temp.: 290°C
Loading pressure: 6 MPa
Driving testL
=1
35
mm
Microscop
e
CCD
Screen
Varifocal
scanner
Laser
BS
Function
Generator
Amplifier
LD
FWMH
69.3
μm
FWMH
82.3
μm
Focus
Defo
c
us
Intensity
Intensity
Po
sitio
n [μm
]P
ositio
n [μm
]
Frequency response; Scanner
0
1
2
3
4
5
6
7
8
3.4 3.45 3.5 3.55 3.6 3.65 3.7 3.75 3.8
Opti
cal
angle
, θ
[deg
.]
Frequency [kHz]
50 V
37.5 V
25 V
The resonant frequency is 3.59 kHz.
The optical angle is 7 deg. at the resonant frequency and 50 V.
θ
Screen
Varifocal scanner
LaserBS
-200
-150
-100
-50
0
50
100
-2.5
-2
-1.5
-1
-0.5
0
0.5
1
-1000 -750 -500 -250 0 250 500 750 1000
Surface profile
Deviation from parabola is less than λ/2 inside of 0.75r.
Def
orm
atio
n [μm
]
Position [μm]
Measured A
Measured B
Fitting curve
500 μm
A
B
Initial
Dev
iati
on f
rom
par
abola
[nm
]
Deviation A
Deviation B
18
0 n
m
Interference fringes of the VM
Focus spot image
Frequency response; VM
0
0.4
0.8
1.2
1.6
2
10 15 20 25 30
150 V
100 V
50 V
Def
orm
atio
n a
t th
e ce
nte
r of
var
ifo
cal
mir
ror
[μm
]
Frequency [kHz]
The deformation is 1.8 μm at 18.6 kHz and 150V.
Minimum focal length is 138 mm
125
208
156
313
625
Inf.
Fo
cal
leng
th [
mm
]
Motion coupling from Scanner frame to VM
0
0.5
1
1.5
2
0
50
100
150
200
10 15 20 25 30
Measured point
Exci
ted
vib
rati
on
am
pli
tud
e [n
m]
Frequency [kHz]
Def
orm
atio
n a
t th
e ce
nte
r o
f
var
ifo
cal
mir
ror
[μm
]
Varifocal mirror
Scanner
1
2
The motion of the varifocal mirror is influenced by the frame
vibration of the varifocal scanner at 22 kHz.
The low coupled area (18.6 kHz) is used for focusing.
Low coupled
Coupled
Low coupled
To
rsio
n s
prin
g d
ire
ctio
n
The varifocal mirror is slightly deformed by the
inertial force caused by the scanner motion.
1
3
Motion coupling from Scanner to VM
Position [μm]
Su
rfac
e p
rofi
le [n
m]
Dy
nam
ic d
efo
rmat
ion
[n
m]
1
4
Motion coupling from Scanner to VM
The deformation is less than λ/10.
光通信シリコンフォトニクス
48
Ultra-small optical circuits for
optical telecommunication
Optical interconnections
in computer chips
Silicon light wave modulator (IBM)
Silicon photonics :Integrated optical circuits
and devices
New Si photonic devices
IBM
3D Chip Stack: (top) optical
NoC
memory layer, (bottom)
processing coreshttp://www.3dincites.com/2015/02/silicon-photonics-2-5d-interposer-design/
シリコンフォトニクス:集積光回路とデバイス
シリコン電子回路+シリコン光回路 どちらもLSI技術利用
シリコンの光透過帯域>1μm
光通信波長(主要帯域):1.5μm
ボンディング技術光源,光検出器は非シリコン系(InP) (Ge)
問題点
電子系,光系の接続,貫通配線
外部とのインターフェイス
MEMS技術による解決
貫通配線
パッケージ
シリコンフォトニクスに期待されるMEMS技術
光集積回路とレーザ/ファイバーの接続
(a),(b) 中空支持導波路
(c) V溝付き接続部
(d) V溝レンズ可動機構付き接続部
C. Li, et.al. Int. Conf. Optical MEMS and Nanophotoics,
(2016) 277.
Q. X. Zhang, el.al. IEEE J. Sel. Top. Quantum Elect., 16, 1
(2010) 267
シリコンとIII-V族半導体の張り合わせ
シリコン基板とIII-V基板の接合によるフォトニックデバイスの製作
(a)(b)InP, (c)GaN
D. Liang, et.al. Elec. Lett., 45, 12 (2009)
578.B. Thubthimthong, et.al. Photon. J. 7, 4 (2015)
7801511.
InP GaN
光集積回路のテストプローブ
(a)
(b) (c)
(d)
Optical waveguide
Compliant probes
光電子集積回路のウエハ試験プローブ,(a)断面構造(b)電気プローブと光導波路,(c)電気プローブ,(d)導波路グレーティング結合器
H. D. Thacker, et.al, J. Sel. Top. Quantum Elec. 17, 3 (2011) 659
M. Geng et.al. Opt. Exp. 17 (2009) 5502
MEMS静電アクチュエータ
導波路スイッチ > 0.4mW/channel
波長可変リング >1mW/nm
応答時間 >100μsec.
Q. Fang et.al. Photon Technol. Lett. 23 (2011) 525
電気光学効果
高速変調器波長可変リング > 0.1nm/V
熱光学効果
導波路スイッチ < 1pJ/channel
波長可変リング ~1nm/V
応答時間 ~10μsec.
Qianfan Xu, et.al. Nature 435(2005) 325
シリコンデバイスのチューニング方法
Compact 1 ×N thermo-optic switches based on silicon photonic wire waveguides, Tao Chu, Hirohito Yamada, Satomi Ishida and Yasuhiko Arakawa, et al., 12 December 2005 / Vol. 13, No. 25 / OPTICS EXPRESS 10114
マッハツェンダー(MZI)型光スイッチ
・熱で屈折率変調・応答速度:約100µs
・消光比:15dB
・消費電力:90mW
熱型シリコン細線導波路光スイッチ
入力出力
導波路マトリクス光スイッチ
2x2スイッチ
シリコン導波路MEMSスイッチ
シリコン導波路結合器MEMSスイッチ,(a)2x2, (b)1x6
シリコン導波路断熱結合器64x64MEMSクロスコネクトスイッチ(a) スイッチマトリクス構成,(b) スイッチ断面構造,(c) 製作されたスイッチ
Y. Akihama, K. Hane, Light: Sci. Appl., 1 (2012)
e16.
T. J. Seok, et.al. Optica 3, 1
(2016) 64.
OFC 2015 M2B.4
Elliptical
bridge
Si freestanding
waveguide
Support
arm
Si freestanding
rib waveguide
Support
arm
Low loss bridge
support
Rib waveguide
support
Basic waveguide support structure for
freestanding waveguide
Submicron wide cross sections
R6µm
2.05µm
Variable-gap Si waveguide coupler switch
Freestanding waveguide
width: 400nm
height: 260nm
Coupling length:10μm
Gap:20-1000nm
Voltage:~30V
* Response time
~10μsec
* Energy consumption
<1pJ per switching
* Actuator
< 60μm square
*Symmetric coupler
arrangement
* Uniform air clad in
coupler region
10μm
58
Gap (nm)
Norm
aliz
ed inte
nsity Through port
Drop port
Simulation of variable-gap coupler
Gap: 100 nm
Simulation by FDTD
Waveguide width : 400nm
thickness: 260nm
Wavelength: 1.55μm
Si refractive index: 3.467
Mode: TE
Co
up
ling
co
effic
ient (μ
m-1
)
Gap (nm)
400nm wide
260nm thick
TE mode
Gap:100nm
Input
Drop
59
Gap : 350nm
Gap : 100nm
input5μm
Switch-on
Switch-off
Motion of fabricated coupler switchOptical microscope image
Actuator voltage < 30V 10μm 60
Input
Drop
Through
Applied voltage is changed from
0V to 30.5V repeatedly at 1.55
μm. Laser power: 80 μW
Optical outputs measured by IR camera
Arrangement of switch
Clear spot images were obtained
at through and drop portsIR camera image
Nearly 100% intensity at
through port is transferred
to drop port under
switch-on condition
Port isolation: 15dB
(at 28.9V)
Wavelength: 1550 nm
Laser power: 80 µW61
)(10 tuVxV
C
qqR
qV
kxxxm
Motion x:displacement, m:mass,γ:dumping coeff.,
equation k:spring const., ℓ:overlap length of comb
Circuit q:excess charge, R:resistance, C:capacitance,
equation V:initial voltage,V0u-1:step voltage
Response time and energy consumption
Response time:~15μs
Energy consumption:~1pJS. Abe et.al. IEEE Photon.Technol.Lett. 26 (2014) DOI:10.1109/LPT.2014.2329033
Calculations Measurement
1x6 switch consisting of five 2x2 switches
Y. Akihama, K. Hane, Light: Sci. Appl., 1 (2012)
e16.
F
E
B
A
C
D
F
E
B
A
C
D
F
E
B
A
C
D
Optical outputs measured by IR camera
Spot images under
switch-on condition
at respective ports
Comparison of
spot images at
respective ports
F port ONE port ON
B port ON
Port isolation: 6.2dB~27.3dB
Cross talk: 6.9dB~28.1dB
Insertion loss: <1dB
(single switch) 64
ミラーとLSIの集積
PACKAGING OF 11 MPIXEL CMOS-INTEGRATED SIGE MICRO-MIRROR
ARRAYS A Witvrouw et.al. IMEC, Philips Applied Technologies, ASML MEMS 2009 136-139
MEMS-type monocrystalline silicon SLM on LSI circuit
T. Sasaki, S. Chernroj, H. Matsuura and K. Hane, OMN 2015 Tu3.3-1F. Zimmer, M. Lapisa, T. Bakke, M. Bring, G. Stemme, JMEMS, 20, pp.564-572 (2011)(a) (b)
100 mm100 mm1 mm
1 mm
In this study, we fabricate the monocrystalline silicon grating on LSI circuit using two step
polymer bonding process and measure the characteristics.
However, the device was not actuated due to the serious electrical damage of LSI. So the
feasibility of fabrication process and characteristics of the grating on LSI is not apparent.
Monocrystalline Si tilt type mirror array on LSI
circuit
Tunable monocrystalline si grating on LSI
circuit
・Drift free characteristics
・Planarization using polishing process
・Simple fabrication process without
planarization
Lens
Grating
Anamorphic
prism
Input fiber
Output fiber
Output fiber
MEMS gratingsMovable ribbonsMEMS gratings
LSI chip
MEMS chip
25
0 r
ibb
on
s
24 channels
MEMS grating:9μm wide, 1μm space400μm long, 250 ribbons1μm-3μm gap
波長選択スイッチ(MEMSグレーティング)Wavelength selective switches using MEMS grating
Ribbon MEMS Optical network
in town
光ビーム走査の原理Principle of light beam steering
MEMS gratings
25
0 r
ibb
on
s
24 channels
LSI chip
MEMS chip
Si gratings
The UR3100 polymer is used as
the bonding pad and anchor of
grating structure.
The Epotek 353ND is used for
filling the space between bonded
silicon membrane and electrode
matrix glass to avoid sticking of
membrane during process.
Capillary
ChannelsCapillary
Channels
Grating Support
Structure
2.6um Spacers
(4)Polymer Patterning (5) SOI wafer bonding (6) Polymer filling
2. Polymer patterning and SOI wafer bonding
(7) Si Handle layer etching (8) SiO2 layer etching (9) Au coating
(11) FAB etching (12) O2 ashing (10)Resist coat/Patterning
3. Grating fabrication
Au/Cr
SiO2 Si
UR3100 Polymer Photo resist Silica sphere
EPOTEK 353ND
Polymer
(1) Au/Cr Sputtering (2)Resist coat/Patterning(3) Au/Cr Etching and
Resist Removing.
1. Electrode Matrix Fabrication
Vacuum chamber
bubbles
Filling bridge
Polymer
Source
Polyamide Tape
Polymer filling technique using Epotek 353ND
Si グレーティングの製作Fabrication of Si gratings
Collaboration with Prof H. Matsuura
(Tohoku Gakuin Univ.)
Fabricated LSI
8 inch wafer
Alignment marks
Electrodes for movable grating
24 channels
Memory and DAC
Ele
ctr
od
es fo
r sig
na
l co
ntr
ol
Supporting part
for MEMS
grating mirrors
12
.5 m
m
25 mm
Memory and DACElectrodes for grating
100μm
Voltage output by program
1cm
100μm
Memory and DAC
Grating
Silicon grating on LSI circuit
LSI上に製作したSiグレーティングFabricated Si grating on LSI
Static characteristics of grating
It is shown that the proposed fabrication process can be utilized for fabrication of tunable
grating on LSI circuit. Stress acting on the grating ribbon is estimated to be 3MPa.
Cross-sectional profiles of ribbon
-0.25
-0.2
-0.15
-0.1
-0.05
0
0.05
0 50 100 150 200 250 300 350 400 450
Hei
gh
t[m
m]
Position [mm]
0 V
2 V
3 V
4 V
4.5 V
5 V
Fit curve (beam with a moment and an in-plane stress)50
0
-50
-
100
-
150
-
200
-
250
He
igh
t [n
m]
-6
-4
-2
0
2
4
6
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
-25 25 75 125 175
Tri
gger
volt
age
for
the
sett
ing o
f
ribbon v
olt
age
[V]
Vel
oci
ty o
f ri
bbon [
arb. unit
]
Time [ms]
Dynamic characteristics of grating
Tc
Under damped characteristic was obtained. The conversing time Tc was about 50 μs.
Velocity and voltage as a function of time
Generation of grating height pattern
Position(µm)
Cro
ss
sectionalpro
file
of
gra
ting
[µm
]
One period
One period
The lineally varying height distribution could be generated roughly.
Position [µm]
2 level
4 level
6 level
One period
Setting height distribution
10 mm
LSIによるSiグレーティングの動作Operation of Si grating by using LSI
Operation of addressed ribbons of gratingSwitching of diffraction pattern
Experimental demonstration by T. Suzuki and T. Sasaki
異種半導体の集積Si+GaN
GaN nanophotonics
- Nonlinear effect (QW optical limiter, 2nd harmonic
generator)
- Pockels effect investigated but on bulk GaN, GaN MZI
(only proposed design, 2016)
Highly integrated systems on chip using Si/GaN
On-chip
transceiver
Waveguides
Off-chip transceiver/
MUX/DEMUX
1, 2, 3
Pockels effect
0
0.2
0.4
0.6
0.8
1T
ran
sm
issio
n
Wavelength
Refractive index change [Saleh & Teich, 2ed, 2007]
3
13
2
GaN
GaN
r n En
0GaNn 0GaNn 0GaNn
Blue-shifting Red-shifting
E = 1 x 10-5 V
r13 = 0.6 pm/V
nGaN = 2.32
nGaN = 5 x 10-7
@ 1 V applied
Key Fabrication Process Features:
Batch processing
Possibly CMOS-compatible, if not using EBL (DUV, etc.)
Independent designs of Si and GaN WG circuit
Processing Tmax = 400 °C
450 nm coupling gap for Si/GaN directional coupling (not too small/large)
GaN MR (top)
Outer Si
ElectrodeInner Si
Electrode
Si Bus SW
(bottom)
Design Fabrication processes
Design and Fabrication
Burried
outer Si
electrode
Burried inner Si
electrodeBuried Si bus WG
(bottom)
GaN MR (top)
Electrode
Electrode
16 um
TE selector
Incoming
TE & TM
Outgoing TE
TE
Design and Fabrication
B. Thubthimthong, et.al. Photon. J. 7, 4 (2015) 7801511.
B. Thubthimthong, et.al. Opti. Express 24,
26(2016)29643
Transmission spectrum measurement (no tuning)
IR image of the excited microring
Qloaded
=
30,00
0
-68
-66
-64
-62
-60
-58
-56
-54
-52
-50
1522.29 1522.59 1522.89 1523.19 1523.49
Tra
nsm
issi
on
(d
B)
Source wavelength (nm()
On-resonanceOff-resonance
Qloaded = λ/Δλ = 1523 nm/50 pm = 30,460
Energy density profile (MPB)
of fundamental TE-like mode, neff = 2.06
Experiments
Static electro-optic tuning
- +----
+
+
+ +
++
++
-
+ -+
+++
--
-
- -
--
--
-
+
+
y = -0.1163x
-15
-10
-5
0
5
10
15
-60 -40 -20 0 20 40 60
Re
so
na
nce
sh
iftin
g (
pm
)
Applied voltage (V)
-70
-68
-66
-64
-62
-60
-58
-56
-54
-50 -40 -30 -20 -10 0 10 20 30 40 50
Tra
nsm
issio
n (
dB
)
Detuning (pm)
60 V
40 V
00 V
-20 V
-40 V
-60 V
Monolithic displacement encoder sensor integrating
GaN LED and Si photodiodes Collaboration with Sanken Electric Co.Ltd.
Design of optical encoder Grating image principle
* Incoherent light source
・・・ 484 nm GaN blue LED
* Object, Scale and Index gratings
・・・ 20 mm pitch
* Photodiode
・・・ Si pn-junction
4-phase-shifted grating
patterned implantation
S.Nagai, T.Sasaki, H.Kawaguchi, A.Iwabuchi, and K.Hane Transducers 2013, 972-97584
Fabricated encoder with LED and Si photodiodes
Whole view of encoder sensor
LED with grating mask Si photodiode patterned by ion implantation
85
Characteristics of GaN-LED and Si-PD
Electroluminescence
image of the fabricated
LED and its intensity
distribution
86
I-V characteristics of the fabricated Si-PD
inset: wavelength responsivity
Voltage (V)
Fabricated photodiode on GaN/Si substrate
Encoder signals and displacement sensing
Encoder measurement setup
・The gap is 4.1 mm, ・Signal periods (10 mm for
lateral displacement, 0.4 mm for gap change)
agree with the theoretical calculations
・ Displacement measurement error is smaller
than 0.15 mm
Encoder signal measured as a function of displacement
87
まとめ
Burried outer
Si
electrode
Burried inner Si
electrode
1.はじめに 国際会議等の傾向など
2.ディスプレイ
3.車載用スキャナ
4.高機能ミラー
5.光通信とシリコンフォトニクス
6.ミラーとLSIの集積
7.異種半導体の集積(Si+GaN)
8.まとめ
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