ƒ ½ ¨ 7 Hë H Sae Mulli (The Korean Physical Society), Volume 55, Number 1, 2007¸ 7 Z 4, pp. 43∼46

 ƒ  ½ ¨ 7 Hë  H  Sae Mulli (The Korean Physical Society), Volume 55, Number 1, 2007¸   7 Z 4, pp. 43∼46

Si (111) M “ ˜ m ü; c V R ËX ê s” X ¢ GaN U c lT c l • «; c 6 ” X ¢ AlN ! a( a• «8 ý W _ Ë] ‚ §

™ »%
¦  ^∗

' õ

AÅ Ò@ /† < Ɠ § „   & ñ ˜ Ð/ B N † < Æ Ò, ' õ AÅ Ò 360-746 (2007¸   4 Z 4 9{ 9  ~ à Î6 £ §)

Ä

»l  o† < Æl  © œ7 £ x ‚ Ã Ì  © œq \  ¦ s 6   x # Œ Si (111) l ó ø Í0 A\  GaN 8 £ x`  ¦ $ í  © œ r v “ ¦ AlN ! Q( 8 £ x ¿ ºa \ 



 É r Õ ª : £ ¤$ í `  ¦ ƒ  ½ ¨ % i  . AlN ! Q(  ¿ ºa  › ¸] X `  ¦ : Ÿ x K  2.6 µm ¿ ºa _  GaN 8 £ x \  µ 1 ÏÒ q t   H ç  H\ P 

` 

¦  © œ{ © œy  y Œ ™™ èr ~  ´ à º e ” % 3  . X-ray diffraction õ  photoluminescence 8 £ ¤& ñ `  ¦ : Ÿ x K  GaN 8 £ x \  @ /ô  Ç AlN ! Q( 8 £ x _  % ò † ¾ Ó`  ¦ S X ‰ “   % i  . AlN 80-nm ¿ ºa \ " f, (002) X-ray rocking curve _  full width at half maximum 8 £ ¤& ñ   õ  437 arcsec _  a % ~“ É r   & ñ $ í `  ¦ ° ú   H ~ à Ì} Œ •`  ¦ % 3 % 3 “ ¦ photoluminescence 8 £ ¤& ñ

 

õ  300 K \ " f 40 meV _  full width at half maximum `  ¦ % 3 % 3  .

PACS numbers: 62.40+i, 81.40.J; 68.55.-a

Keywords: Û ¼à ÔY UÛ ¼, ç  H\ P , z  ´o – B H (111), AlN ! Q( 8 £ x, Ä »l  o† < Æl  © œ7 £ x ‚ à Ì

I. " e  ] Ø

þ

j   H \ , Si l ó ø Í`  ¦ s 6   x ô  Ç GaN _  $ í  © œ~ ½ ÓZ O s  ´ ú §“ É r Å Ò 3

l

q`  ¦ ~ à Γ ¦ e ”  . Si l ó ø Í`  ¦ s 6   x † < ÊÜ ¼– Ð+ ‹ % 3 `  ¦ à º e ”   H  © œ

&

h

“ É r $     o, @ /6   x | ¾ Ó o, Õ ªo “ ¦ a % ~“ É r \ P  x 9  „  l & h  „  

•

¸$ í 1 p x s  e ”  . s  Qô  Ç ´ ú §“ É r  © œ& h \ • ¸ Ô  ¦ ½ ¨ “ ¦ Si l ó ø Í s

 GaN $ í  © œ\   6   x ÷ &t  · ú §  H s Ä »  H GaN ~ à Ì} Œ •_  ç  H\ P  (crack) Ò q t$ í M :ë  H s  . GaN ü < Si l ó ø Í s _   H     © œ Ã

º Ô  ¦{ 9 u ü < \ P Ø Ÿ ‚ ½ Ó> à º_  s  e ” >  ¿ ºa  œ íõ ½ + É M : GaN _  ç  H\ P `  ¦ µ 1 ÏÒ q tr †   . ´ ú §“ É r ƒ  ½ ¨ [ þ t“ É r Si l ó ø Í\ 

"

f ! Q(  (buffer) 8 £ x Ü ¼– Ð $ “ : r GaN \  ¦  6   x l  # Q§ > l  M

:ë  H \  AlN [1], 3C-SiC [2], AlAs [3], Õ ªo “ ¦ HfN [4]_ 

!

Q( 8 £ x`  ¦  6   x # Œ “ ¦¾ ¡ §| 9 , Á ºç  H\ P  GaN \  ¦ % 3 l  0 AK 

”

¸§ 4  “ ¦ e ”  . # Œ Q ! Q( 8 £ x[ þ t ×  æ \ " f ´ ú §“ É r ƒ  ½ ¨ [ þ t“ É r Z

 }“ É r “ : r • ¸\ " f î ß –& ñ ô  Ç AlN ! Q( 8 £ x`  ¦  6   x # Œ “ ¦¾ ¡ §| 9 _  GaN ~ à Ì} Œ •`  ¦ % 3 % 3  . Watanabe [1]  H · û ª“ É r AlN é ß –  & ñ s  Si l ó ø Í 0 A\ " f GaN é ß –  & ñ `  ¦ $ í  © œ   H X < ´ òõ & h “   ! Q (

8 £ xe ” `  ¦ ˜ Г ¦ % i  . Rehder [5]  H Si l ó ø Í0 A\  Ä »l l 



© œ7 £ x ‚ à ÌZ O  (MOVPE : metalorganic vapor phase epitaxy) Ü

¼– Ð $ í  © œô  Ç AlN_  Ó ü t o & h  ½ ¨› ¸ “ : r • ¸ü < V/III q \     y

Œ

™† < Ê`  ¦ ˜ Г ¦ % i  . Õ ª Q
 ´ ú §s   6   x ÷ &  H Ó ü t| 9 e ” \ • ¸ AlN ! Q( 8 £ x \  @ /ô  Ç ƒ  ½ ¨ ™ èà º\  Õ ªu “ ¦ e ”  .



 " f, ‘ : r ƒ  ½ ¨\ " f  H Ä »l  o† < Æl  © œ7 £ x ‚ à ÌZ O  (MOCVD : metalorganic chemical vapor deposi- ton) `  ¦ s 6   x # Œ AlN ! Q( 8 £ x ¿ ºa \    É r Si (111) l 

∗

E-mail: [email protected]

ó ø

Í0 A\  $ í  © œô  Ç GaN ~ à Ì} Œ •_    & ñ $ í _     o x 9  ç  H\ P x 9 • ¸ _

    o\  ¦ ƒ  ½ ¨ % i  .

II. ÷ m Ç] M öU ê s0 n É

GaN ~ à Ì} Œ •“ É r MOCVD (Veeco  , D180GaN)  © œq \  ¦ s  6

x # Œ $ í  © œ ÷ &% 3  . GaN $ í  © œ`  ¦ 0 AK  (111) ~ ½ ӆ ¾ Ó Si (n+ þ A, 0.001Ω·cm) l ó ø Í`  ¦ s 6   x % i  . í ß – oÓ ü t s  \ O   H ³ ð

€

 `  ¦ 0 AK  à º™ è7 á x é ß – Si ³ ð€   % ƒo \  ¦ % i   [6]. AlN ü <

GaN 8 £ x“ É r TMGa, TMAl ü < NH

\  ¦ ™ èÛ ¼ Û ¼– Ð H

\  ¦ H

o # Q Û ¼– Ð  6   x # Œ 1070

C, 76 Torr ü < 1045

C, 200 Torr \ " f y Œ •y Œ • $ í  © œ % i  . AlN ! Q( 8 £ x`  ¦ $ í  © œ  l

 „  , Si (111) l ó ø ͓ É r H

ì  r 0 Al \ " f 1090

C – Ð \ P % ƒ o

 % i  . AlN ! Q( 8 £ x`  ¦ @ /| Ä Ì 35 nm, 65 nm, Õ ªo “ ¦ 80 nm – Ð $ í  © œô  Ç Ê ê 1045

C \ " f €  • 2.6 µm GaN ~ à Ì} Œ •`  ¦ $ í



© œ % i  .

AlN ¿ ºa \    É r GaN _  ç  H\ P x 9 • ¸  H Normalski ‰ & ³p 

 â

(x50) \  _ K  › ' a ¹ 1 Ï ÷ &% 3  . $ í  © œ  ) a ~ à Ì} Œ •_  ½ ¨› ¸\  ¦ › ' a

¹

1 Ï l 0 AK  X-ray diffraction (XRD) 8 £ ¤& ñ `  ¦ % i “ ¦ F  g

†

< Æ& h “   : £ ¤$ í `  ¦ › ' a ¹ 1 Ï l 0 AK  photoluminescence (PL) 8 £ ¤

&

ñ `  ¦ % i  .

III. + s ÇÊ Ý õ m Í À X Ø8 ý

Fig. 1 “ É r Normalski ‰ & ³p  â (x50) Ü ¼– Ð › ' a ¹ 1 Ï  ) a AlN

!

Q( 8 £ x ¿ ºa \     $ í  © œô  Ç GaN ~ à Ì} Œ •_  ³ ð€   ”  s  .

-43-

-44- ô  Dz D GÓ ü t o † < Æ rt  “D hÓ ü t o ”, Volume 55, Number 1, 2007¸   7 Z 4

Fig. 1. (a) ∼ (c)  H AlN ! Q( 8 £ x ¿ ºa  35 nm, 65 nm, Õ ª o

“ ¦ 80nm \ " f €  • 2.6 µm $ í  © œô  Ç GaN ~ à Ì} Œ •\  @ /ô  Ç ³ ð

€

 s  . — ¸Ž  H Ò  re  ¦ \ " f mirror-like ³ ð€  `  ¦ ˜ Ðs “ ¦ e ”  .

AlN ! Q( 8 £ x ¿ ºa  7 £ x † < Ê\    , GaN _  ç  H\ P x 9 • ¸  H è

 H \  ` (>  y Œ ™™ è % i  . 80-nm Ò  re  ¦ _   â Ä º,  _  Á ºç  H\ P 

\

  î  r ³ ð€  `  ¦ ˜ Ðs “ ¦ e ”  . s  ‰ & ³ © œ“ É r Si l ó ø Í0 A GaN ç

 H\ P   © œI  AlN ! Q( 8 £ x \   © œ{ © œy  % ò † ¾ Ó`  ¦ ~ à Î6 £ §`  ¦
 



· p . { 9 ì ø Í& h Ü ¼– Ð, Si l ó ø Í0 A GaN_  ç  H\ P “ É r tensile stress

\

 l “  K  µ 1 ÏÒ q t`  ¦ ô  Ç .   " f, s  Qô  Ç   õ   H AlN ! Q (

8 £ x ¿ ºa  7 £ x  €  " f GaN _  tensile stress  ¢ - a  o÷ &

%

3 l  M :ë  H“    כ Ü ¼– Ð ó ø Íé ß –  ) a  . 35 nm, 65 nm, Õ ªo “ ¦ 80 nm Ò  re  ¦ _  ç  H\ P x 9 • ¸  H y Œ •y Œ • 300 /cm, 40 /cm, Õ ªo “ ¦ 7 /cm s % 3  . 80nm AlN ! Q( 8 £ x`  ¦  6   x # Œ 1 µm $ í  © œô  Ç GaN ~ à Ì} Œ •\ " f Á ºç  H\ P ô  Ç ³ ð€  `  ¦ % 3 `  ¦ à º e ” % 3  .

Fig. 2   H Si (111) l ó ø Í © œ\  AlN ! Q( 8 £ x ¿ ºa \    

$ í

 © œô  Ç GaN ~ à Ì} Œ •\  @ /ô  Ç θ − 2θ Û ¼ ± pô  Ç XRD   õ s  .

—

¸Ž  H GaN ~ à Ì} Œ • Ò  re  ¦ \ " f GaN (0002) €  õ  › ' a >   ) a y © œô  Ç x

ß ¼ 2θ = 34

\ " f › ' a ¹ 1 Ï÷ &% 3  . s [ þ t   õ   H GaN ~ Ã Ì }

Œ

•s  AlN ¿ ºa \   © œ › ' a\ O s  Z  }“ É r c-» ¡ ¤ C † ¾ Ó$ í õ  “ ¦¾ ¡ §| 9 _ 

 

& ñ $ í `  ¦ f ” `  ¦ ˜ Ð# Œï  r  . ¢ ¸ô  Ç, Fig. 2   H AlN (0002)

€

 _  x ß ¼y © œ• ¸ AlN ! Q( 8 £ x ¿ ºa 7 £ x \     y © œK t   H

‰

&

³ © œ`  ¦ ˜ Ðs “ ¦ e ”  .

AlN ! Q( 8 £ x ¿ ºa \    É r GaN 8 £ x _    & ñ $ í `  ¦ · ú ˜ ˜ Ð l

 0 AK  X-ray rocking curve (XRC) 8 £ ¤& ñ `  ¦ % i  . Fig.

3 \  (002) full width at half maximum (FWHM) 8 £ ¤& ñ

 

õ 
 
 e ”  . AlN ! Q( 8 £ x ¿ ºa  7 £ x † < Ê\    , GaN 8 £ x _    & ñ $ í s  7 £ x † < Ê`  ¦ ˜ Ðs “ ¦ e ”  . 35 nm, 65 nm, Õ ªo “ ¦ 80 nm AlN ¿ ºa \ " f_  (002) FWHM “ É r 680 arcsec, 544arcsec, Õ ªo “ ¦ 437 arcsec – Ð y Œ ™™ è % i  . ¢ ¸ ô

 Ç, XRC x ß ¼ y © œ• ¸\  ¦ ˜ Ѐ   AlN ! Q( 8 £ x ¿ ºa  7 £ x † < Ê

\

    (002) FWHM  â Ä º\   H 2.3 C  & ñ • ¸ x ß ¼ y © œ• ¸

†

¾ Ó © œ÷ &% 3  . 2.6 µm $ í  © œô  Ç GaN 8 £ x \ " f 437 arcsec _  (002) FWHM ° ú כ“ É r Si l ó ø Í\ " f $ í  © œô  Ç GaN 8 £ x _  ˜ Г ¦  ) a

 

õ  ×  æ \ " f  © œ{ © œy   Œ •“ É r ° ú כs  . s  ° ú כs  Si l ó ø Í\ " f “ ¦

¾

¡ §| 9  GaN 8 £ x s  $ í  © œ† < Ê`  ¦
 ? /t ë ß – ° ú  “ É r reactor \ " f



 s # Q l ó ø Í\ " f $ í  © œô  Ç GaN 8 £ x _  ° ú כ (∼300 arcsec)

\

 q K  # Œ„  y  Z  }  .

AlN ! Q( 8 £ x ¿ ºa \    É r   & ñ $ í † ¾ Ó © œs  F  g † < Æ& h “   : £ ¤$ í

\

 p u   H % ò † ¾ Ó`  ¦ › ' a ¹ 1 Ï l 0 AK  PL 8 £ ¤& ñ `  ¦ % i  . Fig.

4   H  © œ“ : r \ " f 8 £ ¤& ñ  ) a AlN ! Q( 8 £ x ¿ ºa \    É r GaN 8 £ x _

 PL : £ ¤$ í `  ¦
 ? /“ ¦ e ”  . 35 nm, 65 nm, Õ ªo “ ¦ 80 nm AlN ¿ ºa \ " f_  PL x ß ¼ 0 Au   H 3.41 eV, 3.396 eV, Õ

ªo “ ¦ 3.396 eV % i Ü ¼ 9 AlN ! Q( 8 £ x ¿ ºa  7 £ x  €  " f x

ß ¼ 0 Au  › ¸F Km ”  red-shift ÷ &% 3  .  © œ“ : r \ " f_  PL x  ß

¼ 3.396 ∼ 3.41 eV \ " f › ' a ¹ 1 Ï÷ &% 3   H X < s  ° ú כ“ É r   

Fig. 1. Photomicrographs of the 2.6-µm-thick GaN sur- face for AlN buffer thicknesses of (a) 35 nm, (b) 65 nm, and (c) 80 nm. The numbers of cracks for thicknesses of 35 nm, 65 nm, and 80 nm were 300/cm, 40/cm, and 7/cm, respectively.

s

# Q l ó ø Í0 A\ " f strain relaxation  ) a GaN _  x ß ¼ ° ú כ˜ Ð



 10 ∼ 24 meV ± ú “ É r ° ú כs   [7]. AlN ! Q( 8 £ x ¿ ºa \   



" f
 
  H red-shift ‰ & ³ © œ“ É r Si l ó ø Íõ _  \ P Ø Ÿ ‚ ½ Ó> à º

 ƒ  ½ ¨ 7 Hë  H  Si (111) l ó ø Í0 A\  $ í  © œô  Ç GaN ~ à Ì} Œ •8 £ x \  @ /ô  Ç AlN ! Q( 8 £ x _  % ò † ¾ Ó – ^ ”  ü ½ © -45-

Fig. 2. XRD traces of the GaN films grown on Si (111) substrate with AlN buffer thickness. All of samples have a c plane preferred orientation.

Fig. 3. (002) X-ray rocking curves of GaN layer with AlN buffer thickness.

s \  _ K  biaxial strain  ) a GaN 8 £ x \ " f ˜ Ðs   H PL x  ß

¼   s s  9 s  Qô  Ç ‰ & ³ © œ“ É r GaN \   Œ •6   x   H stress _ 



  o\  _ ô  Ç  כ Ü ¼– Ð ó ø Íé ß –  ) a  . ¢ ¸ô  Ç, AlN ! Q( 8 £ x ¿ ºa 

7

£

x  €  " f x ß ¼ y © œ• ¸  H & h & h  7 £ x  “ ¦ PL FWHM “ É r

&

h

& h  y Œ ™™ è† < Ê`  ¦ ˜ Ðs “ ¦ e ”  . x ß ¼y © œ• ¸_   â Ä º €  • 3.5 C 

&

ñ • ¸ † ¾ Ó © œ ÷ &% 3  . 35 nm, 65 nm, Õ ªo “ ¦ 80 nm AlN ¿ º a

\ " f_  PL FWHM “ É r y Œ •y Œ • 52.4 meV, 45 meV, Õ ªo 

“

¦ 40.3 meV % i  . s    õ   H AlN ! Q( 8 £ x ¿ ºa  7 £ x † < Ê

\

    F  g † < Æ& h “   : £ ¤$ í s  † ¾ Ó © œ H † d`  ¦
  · p .

F 

g † < Æ ‰ & ³p  â õ  PL 8 £ ¤& ñ \ " f
 è ß – AlN ¿ ºa \     stress _     o\  ¦ S X ‰ “   l 0 AK  XRD   õ \  ¦ s 6   x # Œ out-plane stress   õ \  ¦ % 3 % 3  . Fig. 5   H AlN ! Q( 8 £ x

¿

ºa \  @ /ô  Ç GaN ~ à Ì} Œ •_  out-plane stress \  ¦ ˜ Ðs “ ¦ e ” 



. GaN ~ à Ì} Œ •_  out-plane 6 £ x§ 4 “ É r - ° ú כ`  ¦ t  9 tensile

Fig. 4. PL properties of GaN layer with AlN buffer thick- ness at RT.

Fig. 5. Out-plane strains of the GaN layer as functions of the AlN buffer thickness.

stress s   Œ •6   x † < Ê`  ¦ · ú ˜ à º e ” % 3  . GaN ~ à Ì} Œ •_  out- plane stress   H 35-nm Ò  re  ¦`  ¦ ] jü @ Œ 4 H AlN ¿ ºa  7 £ x  €  

"

f ‚  + þ A& h Ü ¼– Ð y Œ ™™ è % i  . 35-nm Ò  re  ¦ _   â Ä º\   H GaN

~ Ã

Ì} Œ •_  out-plane stress  š ¸y  9 y Œ ™™ è % i  . out-plane stress _  y Œ ™™ è  H d ” y Œ •ô  Ç ç  H\ P \  _ ô  Ç GaN ~ à Ì} Œ •_  strain relaxation \  _ ô  Ç  כ Ü ¼– Ð ó ø Íé ß –  ) a  . Õ ª! 3 \ • ¸ Ô  ¦ ½ ¨ 

“

¦, Fig. 5 \  ¦ ˜ Ѐ Œ ¤`  ¦ M : AlN 35-nm Ò  re  ¦ \ " f_  out-plane stress   H AlN 80-nm Ò  re  ¦ _  out-plane stress ˜ Ð   H  כ

`

 ¦ · ú ˜ à º e ”  . Kisielowski   H ü @Â Ò stress \    + þ A ) a GaN 8

£

x“ É r Õ ª ü @Â Ò stress  ] j  ÷ &€   " é ¶ A  t “ ¦ e ” ~   : £ ¤$ í Ü

¼– Ð { 9 & ñ  Òì  r ÷ &[  t  “ : r  “ ¦ ˜ Г ¦ % i   [8]. 7 £ ¤, ç  H\ P  s

 e ”   H GaN ~ à Ì} Œ •“ É r ü @Â Ò 6 £ x§ 4 s  # QÖ ¼ & ñ • ¸ ] j   ) a  © œ I

s # Q" f GaN ~ à Ì} Œ •“ É r # QÖ ¼ & ñ • ¸ strain relaxation  ) a  © œ I

– Ð ÷ &[  t    H  כ Ü ¼– Ð ó ø Íé ß –  ) a  .

-46- ô  Dz D GÓ ü t o † < Æ rt  “D hÓ ü t o ”, Volume 55, Number 1, 2007¸   7 Z 4

IV. + s Ç Â ] Ø

‘

: r ƒ  ½ ¨\ " f  H MOCVD Z O Ü ¼– Ð AlN ! Q( 8 £ x › ¸] X `  ¦ :

Ÿ

x K  Si l ó ø Í0 A\  “ ¦¾ ¡ §| 9  GaN ~ à Ì} Œ •`  ¦ $ í  © œ % i  . é ß –t  AlN ! Q( 8 £ x ¿ ºa  › ¸] X ë ß –Ü ¼– Е ¸ Si( 111) l ó ø Í 0 A\  7 £ x ‚ à Ì

 )

a GaN \ " f_  tensile stress \  ¦ ´ òõ & h Ü ¼– Ð y Œ ™™ èr ~  ´ à º e ”

“ ¦ ¢ ¸ô  Ç   & ñ | 9 `  ¦ † ¾ Ó © œ r ~  ´ à º e ”  . s      õ   H AlN

!

Q( 8 £ x s  Si (111) l ó ø Í 0 A\ " f GaN $ í  © œ\  ×  æ כ ¹ô  Ç % i ½ + É

`

 ¦ † < Ê`  ¦
  · p . 80-nm AlN ! Q( 8 £ x`  ¦ s 6   x # Œ €  • 1 µm ¿ ºa \ " f Á ºç  H\ P  GaN ~ à Ì} Œ •`  ¦ $ í  © œ % i  .

Y

c p w Š à U Ø ”  ô

[1] A. Watanabe, T. Takeuchi, K. Hirosawa, H. Amano, K. Hiramatsu and I. Akasaki, J. Crystal Growth 128, 391 (1993).

[2] T. Takeuchi, H. Amano, K. Hiramatsu, N. Sawaki and I. Akasaki, J. Crystal Growth 115, 634 (1991).

[3] N. P. Perkins, M. N. Horton, Z. Z. Bandic, T. C.

McGill and T. F. Kuech, Mater. Res. Soc. Symp.

Proc. 395, 243 (1996).

[4] R. Armitage, Q. Yang, H. Feick, J. Gebauer, E. R.

Weber, S. Shinkai and K. Sasaki, Appl. Phys. Lett.

81, 1450 (2002).

[5] E. Rehder, M. Zhou, L. Zhang, N. R. Perkins, S. E.

Babcock and T. F. Kuech, MRS Internet J. Nitride Semicond. Res. 4S1, G3.56 (1999).

[6] G. S. Higashi, Y. J. Chabal, G. W. Trucks and K.

Laghavachari, Appl. Phys. Lett. 56, 656 (1990).

[7] S. Chichibu, H. Okumura, S. Nakamura, G. Feuillet, T. Azuhata, T. Sota and S. Yoshida, Jpn. J. Appl.

Phys. 36, 1976 (1997).

[8] C. Kisielowski, J. Kr?ger, S. Ruvimov, T. Suski, J.

W. Ager, E. Jones, Z. Liliental- Weber, M. Rubin, E. R. Weber, M. D. Bremser and R. F. Davis, Phys.

Rev. B 54, 17745 (1996).

Influence of an AlN Buffer Layer on a GaN Layer on Si (111)

Deok Kyu Kim

Division of Electronics and Information Engineering, Cheongju University, Cheongju 360-746 (Received 9 April 2007)

GaN layers were grown on silicon (111) substrates with AlN buffer layers by using metalorganic vapor phase epitaxy, and the variations in the properties of the GaN layers with the thickness of the AlN buffer layer were investigated. Increasing the AlN thickness was found to decrease the stress sufficiently to avoid crack formation in an overgrown, thick (2.6 µm) GaN layer. X-ray diffraction and photoluminescence measurements were used to determine the influence of the AlN thickness on the strain in subsequent GaN layers. For 80-nm-thick AIN, the full width at half maximum of the (002) X-ray rocking curve was 437 arcsec, and the full width at half maximum of the bound exciton line was as low as 40 meV at 300 K.

PACS numbers: 62.40+i, 81.40.J; 68.55.-a

Keywords: Stress, Crack, Silicon (111), AlN buffer, Metalorganic chemical vapor deposition

∗

E-mail: [email protected]