½ ¨ 7 Hë H Sae Mulli (The Korean Physical Society), Volume 52, Number 5, 2006¸ 5 Z 4, pp. 474∼477
º ºP } º§ 7 0Y (Photo-lithography) M ø n Úù p § T Ó Þ X ¢ 6 ì ÅX ì Ä
x ¢Ñ ÷T # a ¹ Å £ ; < gX c l õ m Í GaN x ¢Ñ ÷T # a ¹ ÅM X ì Äß Ã Å ¤V R Ë ì Å
T
û B ÷ 7 B · »? ý ¡ · T ç ¡ - ! H ∗
· ¡ ¤ @ / < Æ § ì ø Í ¸^ õ < Æl Õ ü t < Æõ , ì ø Í ¸^ Ó ü t$ í ½ ¨ è, Å Ò 561-756
) ç
 6 Ò¦ · L |g Y @ . >
[ j@ / < Æ § [ j b / B N < Æõ , " fÖ ¦ 120-749 (2005¸ 12 Z 4 21{ 9 ~ Ã Î6 £ §)
:
r 7 Hë H \ " f H í Ðo èÕ ªA x / B N& ñ l Õ ü t` ¦ s 6 x # @ / & h Ü ¼ Ð ¸ü <s # Q\ ¦ ] j l 0 Aô Ç l Õ
ü
t` ¦ è> h % i Ü ¼ 9 s \ ¦ s 6 x # { 9 " é ¶& h gallium nitride (GaN) ¸ü <s # Q_ l & h : £ ¤$ í ` ¦
~ 1
> 8 £ ¤& ñ ½ + É Ã º e H ~ ½ ÓZ O ` ¦ ½ ¨ % i . o < Æl © 7 £ x Ã Ì (CVD) ~ ½ ÓZ O Ü ¼ Ð ½ + Ë$ í ) a GaN ¸ü <s # Q H 2 é ß > í Ðo èÕ ªA x / B N& ñ Ü ¼ Ð Back-gate > ´ òõ à Ô ½ t Û ¼' (field-effect transistor) ½ ¨ ¸_ + þ AI
Ð ] j ÷ &% 3 Ü ¼ 9 gate modulation : £ ¤$ í \ _ K ¸Ø ¦ K · p GaN ¸ü <s # Q_ H o # Q s 1 l x ¸ H 60 ∼ 70 cm
2/Vs Ð ì r í÷ &% 3 . : r z ´+ « >` ¦ : x # ~ 1 > & h É r q 6 x Ü ¼ Ð ´ ú § É r ª _ GaN ¸ü <s # Q_ l
& h : £ ¤$ í õ ì r í\ ¦ ½ + É Ã º e 6 £ §` ¦ S X ½ + É Ã º e % 3 Ü ¼ 9 Æ Ò Ð $ í © ) a GaN ¸ü <s # Q_ F « Ñ
&
h : £ ¤$ í \ @ /K " f ¸ 7 H _ % i .
PACS numbers: 73.50.-h, 73.61.Tm
Keywords: ¸ü <s # Q, í Ðo èÕ ªA x , GaN nanowires, Field-Effect Transistor (FET)
I. " e  ] Ø
&
³F _ ì ø Í ¸^ l Õ ü t É r 9 \ _ Á º# Q_ Z O g Ë :\ _ K Õ ª ß
¼l \ ¦ > 5 Å q& h Ü ¼ Ð × ¦e Ü ¼ Ð" f > 5 Å q& h Ü ¼ Ð µ 1 Ï ¦ e
. s Qô Ç ì ø Í ¸^ µ 1 Ï l Õ ü t` ¦ ó ø Íé ß H MOS à Ô
½ t Û ¼' _ > s à Ô U ´s H 2004¸ \ s p ¸ß ¼l 90nm s % 3 Ü ¼ 9 > 5 Å q& h Ü ¼ Ð Õ ª U ´s × ¦ # Q[ þ t # Q 2010¸
\
H 15nm s | ¨ c כ Ü ¼ Ð } © ÷ & ¦ e . > s à Ô U ´ s
\ ¦ × ¦ s l 0 AK " f H © H l Õ ü t& h © E כ ¹ É r p [
jô Ç J ` ¦ ] j ½ + É Ã º e H o èÕ ªA x l Õ ü t s ½ + É Ã º e
. o èÕ ªA x l Õ ü t _ µ 1 Ï \ O s H l Õ ü t& h ô Ç> \ ¦ F
G4 ¤ l # Q 9Ö ¦ כ s . s Qô Ç F g < Æ& h ô Ç> \ ¦ F G 4
¤ l 0 AK " f H & ³F 2t ~ ½ ÓZ O Ü ¼ Ð K Õ þ s ¸Ò o÷ &
¦ e . Õ ª ' Í P : l > r _ ì ø Í ¸^ o èÕ ªA x l Õ ü t _
ô Ç> \ ¦ D h Ðî r F g " é ¶ 1 p x` ¦ s 6 x # K 9 H l Õ ü t
Ð" f “top-down” l Õ ü t s 9 DUV (deep UV), EUV (extremly-deep UV) o èÕ ªA x , X-ray, c , s : rc o
èÕ ªA x 1 p x s e . ¿ º P : ~ ½ ÓZ O É r D h Ðî r F g " é ¶` ¦ :
x ô Ç o èÕ ªA x ~ ½ ÓZ O s $ " é ¶& h Ü ¼ Ð ¸ß ¼l
∗
E-mail: sk [email protected]
_
Ó ü t| 9 ` ¦ ½ + Ë$ í r & " f s [ þ t` ¦ s 6 x # x 9 F g è
\ ¦ ] j H ~ ½ ÓZ O Ü ¼ Ð" f “bottom-up” l Õ ü t s ¦ ô Ç
. s Qô Ç ì ø Í ¸^ _ $ " é ¶ (low-dimensional, 0D and 1D) ¸½ ¨ ¸[ þ t 7 £ ¤, ì ø Í ¸^ ¸ü <s # Q (semiconductor nanowire) ü < ò ø Í è ¸È ÓÚ Ô (carbon nanotube)1 p x É r & ³F Õ
ª ß ¼l x 9 l , F g < Æ& h Ä ºÃ ºô Ç : £ ¤$ í Ü ¼ РÒ' ¸ß ¼ l
Ð / F g è \ ¦ ] j H X < D h Ðî r ½ ¨ ì r Ð Ö ¸ µ
1 Ïô Ç ½ ¨ ' ÷ & ¦ e [1-4]. : x © & h Ü ¼ Ð 1D ¸ ü
<s # Q1 p x` ¦ s 6 x # è \ ¦ ] j < Ê\ e # Q" f H è
_ ß ¼l Ü ¼Ù ¼ Ð c õ s : rc o èÕ ªA x l Õ
ü
t 1 p x s s 6 x ) a . Õ ª Q s : rc õ c ` ¦ s 6 x ô Ç ~ ½ Ó Z O
É r r ç ß õ q 6 x s ´ ú §s èכ ¹÷ & 9 Ò re ¦ ] j s # Q 90 >
´ ú
§ É r è \ ¦ ] j H X < e # Q" f ´ ú § É r é ß & h ` ¦ t ¦ e
. s \ : r 7 Hë H \ " f H l > r _ : x& h ³ ðï r í Ðo è Õ
ªA x / B N& ñ ~ ½ ÓZ O ` ¦ s 6 x # ¸ü <s # Q_ l & h : £ ¤
$ í
` ¦ ½ ¨ % i . s ~ ½ ÓZ O É r & ³F 6 x H z ´o B H J ?s (
(4-10) 0 A\ ´ ú § É r ª _ ¸ü <s # Q @ /ô Ç l & h : £ ¤
$ í
÷ r ë ß m Õ ª[ þ t _ l & h : £ ¤$ í ì r í\ ¦ · ú Ã º e > K
ï r . s Qô Ç õ H ¸ü <s # Q ½ + Ë$ í õ & ñ \ feedback
÷
&# Q ¾ ÓÊ ê Ä ºÃ ºô Ç ¸ü <s # Q\ ¦ ½ + Ë$ í H X < l # ½ + É כ s
. : r 7 Hë H \ " f H ~ 1 ¦ ç ß é ß > ¸ü <s # Q è [ þ t
-474-
½ ¨ 7 Hë H í Ðo èÕ ªA x (Photo-lithography) l Õ ü t` ¦ s 6 x ô Ç· · · – s 5 p x6 x 1 p x -475-
Fig. 1. (a) ∼ (d) SEM images of GaN nanowires on patterned SiO
2/Si wafer.
\
@ /ô Ç l & h : £ ¤$ í ` ¦ ~ 1 > S X ½ + É Ã º e H ~ ½ ÓZ O ` ¦
è> hô Ç .
II. ÷ m Ç ] M ö
: r z ´+ « >\ 6 x ) a Ò re ¦ É r horizontal hot-wall chemical vapor deposition (CVD) ~ ½ ÓZ O Ü ¼ Ð $ í © ) a GaN ¸ü <
s
# Q s 9 $ í © \ 6 x ) a l ó ø Í É r C-plane s # Qs .
800 ∼ 1000
◦C \ " f VLS (vapor-liquid-solid) $ í © ` ¦ 0 A K
Ni 8 ú ¤ B \ ¦ 6 x % i Ü ¼ 9 Ga x 9 N èÛ ¼ Ð H Ga F K5 Å q õ
NH3 Û ¼\ ¦ 6 x % i . [ j Ò& h ¸ü <s # Q $ í ©
\
' a ô Ç ? /6 x É r Æ Ò& h à Р¦ë H ³\ " f S X ½ + É Ã º e [3]. l & h : £ ¤$ í ` ¦ S X l 0 AK back-gate + þ AI _
>
´ òõ à Ô ½ t Û ¼' (FET) ½ ¨ ¸\ ¦ ½ ¨ & ³ % i . : r z ´+ « >\
"
f H 5 “Cr Û ¼ß ¼ 2> h 6 x ÷ &% 3 . Ò re ¦/ B N& ñ É r 4” z ´ o
B H J ?s ( (n-type, 100, resistivity 5 ∼ 10 Ωcm) \ ¦ 6
x % i Ü ¼ 9 4 “/ B N& ñ x 9 ¸y Ò re ¦ / B N& ñ 1 p x ¿ ºt / B N& ñ ` ¦ z
´r % i . ' Í P : Û ¼ß ¼ H Fig. 1 (a) \ " f Ð H ü <
° ú
s 8 £ ¤& ñ ` ¦ 0 Aô Ç H J _ Û ¼ß ¼s 9 s \ ¦ s 6 x #
\ P
& h Ü ¼ Ð $ í © ) a z ´o B H í ß o} (750 nm) 0 A\ F K5 Å q8 £ x (Ti/Au = 30/100 nm) lift-off / B N& ñ ` ¦ l 0 Aô Ç Û ¼ß ¼s
. Lift-off / B N& ñ Ê ê IPA 6 xÓ o\ { e H GaN ¸ü <s
#
Q\ ¦ Ò re ¦ 0 A\ S X í ß r Ê ê ¿ º P : Û ¼ß ¼\ ¦ s 6 x # Fig. 1 (b ∼ d) \ " f Ð H כ õ ° ú É r ¸ü <s # Q_ èÛ ¼ (source) x 9 × ¼Y U (drain) F G Ü ¼ Ð 6 x > | ¨ c F G
`
¦ J ` ¦ ô Ç . Æ Ò& h Ü ¼ Ð 7 £ x Ã Ì ) a F G (Ti/Au) _ ¸ b
] X 8 ú ¤` ¦ 0 AK 750
◦C, N
2ì r 0 Al \ " f 60 íç ß \ P % o \ ¦
Fig. 2. (a) SEM image, (b) photoluminescence spectra with the 325 nm line of a He-Cd CW laser, (c) typical TEM image, and (d) X-ray diffraction spectra of GaN nanowires grown on sapphire substrate.
% i . \ P % o H RTA (rapid thermal annealing) © q
\
¦ s 6 x # s À Ò# Q& . Fig. 1 É r 2 _ o èÕ ªA x / B N
&
ñ x 9 GaN ¸ü <s # Q / B N& ñ ` ¦ : x K ] j ) a Ò re ¦ _
&
³p â s . ] j ) a Ò re ¦ à Ô ½ t Û ¼' (FET½ ¨ ¸) _
l & h 8 £ ¤& ñ É r semiconductor parameter analyzer (HP4155) ) a probe station \ " f z ´r % i Ü ¼ 9 8 £ ¤
&
ñ : r ¸ H © : r` ¦ Ä »t % i .
III. + s ÇÊ Ý õ m Í À X Ø8 ý
Fig. 2 H s # Q l ó ø Í (1 × 0.5 cm
2) 0 A\ " f o < Æl © 7
£
x Ã Ì ~ ½ ÓZ O Ü ¼ Ð $ í © ) a GaN ¸ü <s # Q_ (a) SEM, (b) photoluminescence, (c) TEM, Õ ªo ¦ (d) X-ray diffrac- tion Û ¼& 7 à Ô! 3 ` ¦ y y Ð# ï r . GaN ¸ü <s # Q H
s # Q l ó ø Í0 A\ ^ & h Ü ¼ Ð ì r í\ ¦ ¦ e Ü ¼ 9 t 2 £ §
É r 100 nm s s ¦ ¸ü <s # Q_ U ´s H à º µm e ` ¦
· ú
à º e (Fig. 2a). Fig. 2(c) H GaN ¸ü <s # Q_ [001] » ¡ ¤ Ü ¼ Ð High-resolution TEM ` ¦ Ð# Å Ò 9 # l
" f wurzite½ ¨ ¸_ GaN ¸ü <s # Q\ ¦ S X ½ + É Ã º e
. Fig. 2(d) H a = 0.319 nm Õ ªo ¦ c = 0.519nm_
© à º\ ¦ ° ú H wurzite ½ ¨ ¸_ GaN ¸ü <s # Q_ X-ray powder diffraction J ` ¦ Ð# Å Ò ¦ e . Fig. 3(a) É r Si l ó ø Í0 A\ e H d ç / å J GaN ¸ü <s # Q_ > s à Ô · ú (+30 V ∼ −10 V) _ o\ É r À Ó- · ú (I
D- V
DS) :
£ ¤$ í ` ¦ Ð# Å Ò 9 Fig. 3(b) H GaN ¸ü <s # Q_ > s à
Ô · ú _ o\ É r × ¼Y U À Ó (I
D) : £ ¤$ í ` ¦ Ð# ï r
-476- ô Dz D GÓ ü t o < Æ rt “D hÓ ü t o ”, Volume 52, Number 5, 2006¸ 5 Z 4
Fig. 3. (a) Gate voltage dependent ID-VDS data recorded on single GaN nanowire, (b) Drain current as a function of the gate voltage at different source-drain voltage.
. Fig. 3\ " f · ú Ã º e 1 p w s > s à Ô · ú _ 7 £ x H
¸ü <s # Q G V , s accumulation (» ¡ ¤& h ) H d Ü ¼ Ð" f × ¼Y U
À Ó (I
D) 7 £ x < Ê` ¦ · ú Ã º e . ¢ ¸ô Ç s õ \ ¦ : x K
"
f GaN ¸ü <s # Q © { © y H o # Q 0 l x ¸ Z }6 £ § õ 1 l x r
\ Ã ºH o # Q n-type ì ø Í ¸^ e ` ¦ · ú Ã º e
. ´ ú § É r bulk GaN \ @ /ô Ç ½ ¨\ Ø Ô ¸i ç s ÷ &t
· ú
§ É r GaN s n-type% ! 3 + þ A$ í s ÷ & H X < s H / B N& ñ ` ¦
H 1 l x î ß | 9 è 4 R ¢ ¸ H í ß è B j» 1 Ïs Ô ¦í H Ó
ü
t Ð 6 x` ¦ ½ + É Ã º e l M :ë H s [5,6]. Õ ªo ¦ 0 A z ´ +
«
> õ [ þ t` ¦ ½ ÓÜ ¼ Ð n-type GaN ¸ü <s # Q_ H o
#
Q 0 l x ¸ü < H o # Q s 1 l x ¸\ ¦ 8 £ ¤& ñ % i . H o # Q 0 l x ¸\ ¦ 8
£ ¤& ñ l 0 AK " f & ñ 6 x | ¾ Ó É r 6 £ § d Ü ¼ Ð > í ß ÷ &% 3 .
C ∼ 2πε
0εL/ln(2h/r) # l " f h H dielectric _ ¿ ºa s ¦
r É r GaN ¸ü <s # Q_ ì ø Ít 2 £ § U ´s s . H o # Q x 9
¸ H n
e= Q/eπr
2L d \ _ K " f → 10
19cm
−3Ü ¼ Ð 8 £ ¤& ñ
÷
&% 3 ¦ s z ´+ « >\ 6 x ) a GaN ¸ü <s # Q s 1 l x ¸ H GaN ¸ü <s # Q Back-gate FET_ transconductance\ _
K 60 ∼ 70 cm
2/Vs Ð 8 £ ¤& ñ ÷ &% 3 .
IV. + s Ç Â ] Ø
: r 7 Hë H \ " f H o < Æl © 7 £ x à Ì~ ½ ÓZ O Ü ¼ Ð $ í © ) a GaN
¸ü <s # Q\ ¦ s 6 x # l & h è \ ¦ ] j < Ê\ e # Q" f l
> r \ V , o 6 x ÷ & H s : rc õ c o èÕ ªA x ~ ½ Ó Z O
\ @ /ô Ç õ ô Ç r ç ß õ q 6 x \ @ /ô Ç é ß & h ` ¦ Ð ¢ - a l 0
AK q §& h s Ý ¼ H ¸ü <s # Q l & h : £ ¤$ í ` ¦
: x& h ³ ðï r í Ðo èÕ ªA x / B N& ñ ~ ½ ÓZ O ` ¦ s 6 x # ~ 1
¦ ç ß ¼ # > l & h : £ ¤$ í ` ¦ % 3 ` ¦ Ã º e Ü ¼ 9 ´ ú § É r ª _
è \ ¦ ] j l 0 AK " f H Ò re ¦` ¦ ¸y Ü ¼ Ð Ø Ôt
· ú
§ ¦ H s Ý ¼ J ?s ( \ ¦ 6 x ½ + É Ã º e 6 £ §` ¦ S X % i .
P
c p 8 ý ò k >
s
7 Hë H É r 2005¸ ¸ < Ʋ D G < ÆÕ ü t < É ª F é ß _ ¸ ½ ¨
t " é ¶ \ O \ _ # ½ ¨÷ &% 3 6 £ § (KRF-2004-041- C00118).
Y
c p w à U Ø ô
[1] Y. Xia, P. Yang, Y. Wu, B. Mayers, B. Gates, Y. Yin, F. Kim and H. Yan, Adv. Mater. 15, 353 (2003).
[2] J. Goldberger, R. He, Y. Zhang, S. -K. Lee, H. Yan, H. -J. Choi and P. Yang, Nature 422, 599 (2003).
[3] J. C. Johnson, H. -J. Choi, K. P. Knutsen, R. D.
Schaller, P. Yang and R. J. Saykally, Nature Mater 1, 106 (2002).
[4] Y. Huang, X. Duan, Y. Cui and C. M. Lieber, Nano.
Lett. 2, 101 (2002).
[5] T. Kuykendall, P. Pauzauskie, S.-K. LEE, Y. Zhang, J. Goldberger and P. Yang, Nano. Lett. 3, 1063 (2003).
[6] J. I. Pankov, T. D. Moustakas, Gallium Nitride
(GaN) I, R. K Willardson and E. R. Weber, Eds,
Semiconductor and Semimetals, (Academic Press,
San Diego, 1998), p. 259.
½ ¨ 7 Hë H í Ðo èÕ ªA x (Photo-lithography) l Õ ü t` ¦ s 6 x ô Ç· · · – s 5 p x6 x 1 p x -477-
Electrical Characteristics of Large-Area GaN Nanowires Using Conventional Standard Photolithography
Seung-Yong Lee, Tae-Hong Kim and Sang-Kwon Lee
∗Department of Semiconductor Science and Technology,
SPRC, Chonbuk National University, Jeonju 561-756
Han-Kyu Sung and Heon-Jin Choi
Department of Ceramic Engineering, Yonsei University, Seoul 120-749 (Received 21 December 2005)
We report simple techniques for extracting the electrical properties of 1-dimensional semiconduc- tor nanowires using conventional standard photo-lithography instead of e-beam lithography (EBL), which is a commonly used technique for the fabrication of nanoscale electrical devices. For the elec- trical transport measurement, the gallium nitride nanowires (GaNNWs) were prepared by using a horizontal hot-wall chemical vapor deposition (CVD), and the GaN nanowire field-effect-transistor (FET) structures on SiO
2/Si wafers were fabricated by using ordinary 2-mask photolithography processes. The carrier mobility estimated from the gate-modulation characteristics iwas on the order of 60 ∼ 70 cm
2/Vs. We found that our approach was a powerful technique for extracting the electrical properties from many semiconductor nanowires The material characteristics of the GaN nanowires is also discussed.
PACS numbers: 73.50.-h, 73.61.Tm
Keywords: Nanowire, Photo-lithography, GaN nanowires, Field-Effect Transistor (FET)
∗
