THE EFFECT OF HYDROGEN ON DISLOCATION PHOTOLUMINESCENCE IN SILICON

HAL Id: jpa-00223049

https://hal.archives-ouvertes.fr/jpa-00223049

Submitted on 1 Jan 1983

HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci- entific research documents, whether they are pub- lished or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.

L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

THE EFFECT OF HYDROGEN ON DISLOCATION PHOTOLUMINESCENCE IN SILICON

Yu. Ossipyan, A. Rtishchev, E. Steinman

To cite this version:

Yu. Ossipyan, A. Rtishchev, E. Steinman. THE EFFECT OF HYDROGEN ON DISLOCATION PHOTOLUMINESCENCE IN SILICON. Journal de Physique Colloques, 1983, 44 (C4), pp.C4-255- C4-259. �10.1051/jphyscol:1983430�. �jpa-00223049�

THE EFFECT OF HYDROGEN ON DISLOCATION PHOTOLUMINESCENCE IN SILICON

Yu.A. Ossipyan, A..M. Rtishchev and E.A.. Steinman

Institute of Solid State Physios of the V.S.S.R. Academy, of Sciences, 142432 Chernogolovka, V.S.S.R.

Résume - On a étudié 1'influence des conditions de déformation plastique sur l'intensité de différentes lignes des spectres de luminescence du sili- cium produites par les dislocations. Par comparaison avec les résultats des signaux de résonance de spin, on montre que la partie courte longueur d'onde du spectre est liée aux dislocations fraiches, tandis que la partie grande longueur d'onde correspond à des transitions électriques mettant en jeu des dislocations ou bien reconstruites ou bien décorées. On discute dans le cadre de ce modèle le changement du spectre de luminescence par hydrogénation.

Abstract - The influance of deformation conditions on inten- sity different lines of dislocation luminescence spectra in silicon has heen discovered. Comparison of these data with the results on the annealing ESE signal showes that short wavelength part of the spectrum is connected with fresh dis- locations, while long wavelength part is corresponded to electron transitions with participation of either reconstruc- ted or decorated dislocations. In this model the change of luminescence spectrum under hydrogenation is discussed.

A great interest in the effect of hydrogen on the behaviour of amor- phous materials has arisen from the possibility to control electri-

cal properties of hydrdgenated amorphous silicon (a-Si) /!/• Howe- ver, the changes produced by hydrogen in structure of amorphous ma- terials remain obscure to the present day. Hydrogen is considered, among other things, to saturate dangling bonds which are found to be one of the principal defects in amorphous semiconductors of the IV group. Nearly complete disappearance of the BSE signal in hydro- genated a-Si / 2 / is direct and effective evidence that dangling bonds are neutralized at the cost of covalent interaction with hyd- rogen atoms. It is of interest, in this connection, to examine the effect of hydrogen on dislocation properties in crystalline silicon"

(c-Si), wich were known to contain a great amount of dangling bonds.

In the present paper dislocation properties were observed with the help of the dislocation luminescence spectrum discovered earlier /3>/» It should be noted, however, that the dislocation luminescence spectrum is found to display a considerably more complex structure than it has been reported in /3/, and it's nature is greatly depende nt on the conditions of introducing dislocations, which eventually determine the dislocation structure /4/. The first part of the paper is devoted to the description of the luminescence technique, hydro-

Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1983430

JOURNAL DE PHYSIQUE

genation procedures of p l a s t i c a l l y deformed samples and c o n d i t i o n s f o r p l a s t i c deformation. The second p a r t d e a l s w i t h t h e dependence of photoluminescence s p e c t r a of specimens on t h e c o n d i t i o n s of p l a s - t i c deformation and subsequent h e a t treakment, w i t h luminescence s p e c t r a of hydrogenated samples and t h e d i s c u s s i o n of t h e experimen- t a l d a t e obtained.

EXPERIMENTAL

I n i t i a l samples were c u t o u t i n t h e form of b a r s measuring 3 x 3 ~ 8 mm 3 w i t h t h e edge o r i e n t a t i o n of (111)

,

,

o r i e n t a t i o n (100)

,

,

.

9

cence s p e c t r a p l a t e s 3 ~ 3 ~ 0 . 5 mm i n s i z e were c u t o u t of t h e defor- med samples and p o l i s h e d chemically i n t h e s o l u t i o n HF:HNO

Luminescence was e x c i t e d by an argon l a z e r w i t h a wavelengzil:Z*

514 nm. The samples were placed i n an o p t i c a l c r y o s t a t enabling t h e measurement temperature t o be maintained i n t h e range of 2-150 K, The luminescence s p e c t r a were recorded u s i n g a high-transmission w a i t i n g monochromator w i t h an a p e r t u r e of 1: 3,5. The samples were hydrogenated p r o on i m p l a n t a t i o n w i t h an energy of 180 kev and doze up t o Lot8 cm-8 and then annealed a t 200-350°C, hydrogen d i f

-

f u s i n g deep i n t o t h e samples. I n a d d i t i o n , t h e method of hydrogenat- i o n samples i n a glow d i s c k a r g e was a p p l i e d t h e r e t o p r e v e n t t h e s u r f a c e l a y e r from being h e a v i l y d i s t r o y e d . The samples were dehyd- rogenated by a n n e a l i n g a t 600-650°C.

EXPERIMENTAL RESULTS AND DISCUSSION

The shape and i n t e n s i t y of i n d i v i d u a l luminescence bands proved t o be dependent on t h e p l a s t i c deformation temperature of t h e sample.

Fig.1 e x h i b i t s luminescence s p e c t r a of t h e samples c o n t a i n i n g appro- x i m a t e l y an equal number of d i s l o c a t i o n s but deformed a t d i f f e r e n t temperaS;ures. The bottom curve demonstrates t h e spectrum of a sample a f t e r a n n e a l i n g a t 8 0 0 0 C . It i s w e l l seen t h a t t h e e l e v a t e d tempera- t u r e of deformation i s r e s p o n s i b l e f o r a d e c r e a s e i n a r e l a t i v e in- t e n s i t y of a s h o r t wavelength s i d e of t h e spectrum, A t t h e same time

one can observe a narrowing of s e p a r a t e spec-

-

C annealing. A l l t h e samples produced by such

3 deformation can c o n d i t i o n a l l y be devided in-

> t o two groups: t h e samples deformed a t tempe-

a c r a t u r e s above and below 700°C. The former 5 d i s p l a y , a s a r u l e , two i n t e n s i v e d i s t i n c t 3 l i n e s w i t h maxima a t e n e r g i e s of 0,80 ev and

s 0,87 ev and a weakly pronounced s h o r t wave-

ZI l e n g t h p a r t of t h e spectrum i n t h e range of

!= 0 , 8 8 - 1 , O ev. I n t h e l a t t e r one f i n d s a grea-

V) z t e r i n t e g r a l i n t e n s i t y i n t h e short-wave

? spectrum p a r t . Under some deformation condit-

5

W i o n s t h e r e a r e r e s o l v e d s e p a r a t e l i n e s , t h e

v E

v w w

2

-

3 s p e c t r a on t h e p l a s t i c deformation temperatu- r e of samples ( i n d i c a t e d on p l o t s ) . The bot-

,,

a f t e r a n n e a l i n g a t a temperature above 8 0 0 ~ ~

impurity surroundings of d i s l o c a t i o n s i n t h e temperature range about 7W0C. A similar "threshold" dependence of t h e behaviour of p l a s t i - c a l l y deformed c r y s t a l s i s a l s o d i s c l o s e d by o t h e r methods /.5-7/.

It i s seen from Fig. 1 b,c t h a t a d e c r e a s e i n t h e s h o r t wavelength l i n e s i n t e n s i t y i s accompanied by a corresponding r i s e i n t h e inten- s i t y of bands 0,80 and 0,87 ev. A t such deformation t h e amount of d a n g l i n g bonds c o n t r i b u t i n g t o t h e ESR s i g n a l i s known t o d e c r e a s e below t h e s e n s i t i v i t y l i m i t / 5 , 8 / . I f a r e d u c t i o n i n t h e number of u n s a t u r a t e d bonds p o i n t s t o t h e rearrangement i n t h e s p i n system then by means of low-temperature deformation we i n t r o d u c e d i s l o c a t - i o n s having t h e h i g h e s t number of unpaired s p i n s , and a correspon- d i n g growth of t h e s h o r t wavelength spectrum p a r t t a k e s account of t h e r e l a t i o n s h i p between t h e observed bands and u n s a t i s f i e d bonds.

On t h e o t h e r hand, t h e r e s u l t s i n /9/ show t h a t lowering t h e defor- mation temperature p e r m i t s one t o i n t r o d u c e d i s l o c a t i o n s surrounded by a l e s s dense impurity atmosphere than a t high-temperature defor- mation. Elevated deformation temperatures o r a subsequent high-tem- p e r a t u r e annealing of t h e samples deformed a t low temperatures may encourage t h e formation of i m p u r i t y atmospheres. I n /4/ we have r e p o r t e d on some c o r r e l a t i o n between t h e i n t e n s i t y of t h e l i n e 0,80 ev and oxygen content i n t h e s t a r t i n g samples. Yet t h e deformed sam- p l e s h e a v i l y doped w i t h o t h e r i m p u r i t i e s such a s copper, aluminium, z i n c demonstrated no marked change i n t h e d i s l o c a t i o n spectrum. I n t h i s connection we b e l i e v e t h e l i n e s observed i n t h e photolumines- cence t o be, seemingly, due t o e l e c t r o n t r a n s i t i o n s onto d i s l o c a t i - on energy l e v e l s . From t h i s p o i n t of view, two s t a t e s of d i s l o c a t i o n s t r u c t u r e t h e r e w i t h may be d i s t i n g u i s h e d i n t h e c r y s t a l s : f r e s h d i s - l o c a t i o n s introduced a t t h e lowest temperatures, r e l a x e d d i s l o c a t i a i n t r o d u c e d a t a temperature above 7 0 0 ~ ~ and t h o s e annealed i n t h i s temperature range. The f i r s t s t r u c t u r e conforms t o t h e luminescence spectrum w i t h t h e i n t e n s i v e s h o r t wavelength s i d e 0 , 8 8 4 ev (fig.la), t h e second does t o 'the spectrum, i n which only t h e long-wave l e n g t h s i d e 0,8-0,88 ev w i t h more i n t e n s i v e l i n e s of 0,80 ev and 0,87 ev i s p r a c t i c a l l y found t o occur ( F i g . 1 ~ ) . I n t h i s c a s e t h e d i s l o c a t - i o n s from t h e second s t a t e can be t r a n s f e r r e d t o t h e f i r s t one u s i n g a s h o r t deformation a t t e n d i n g t h e thermal impact d u r i n g t h e quen- ching of t h e samples. T h i s l e a d s t o simultaneous t r a n s f o r m a t i o n of t h e spectrum from t h e c- o r d-type t o t h e a-type i n Fig.1. S i m i l a r quenching of t h e i n i t i a l samples f a i l s t o b r i n g about t h e occurrence of any l i n e s i n t h i s spectrum range.

T h e - d a t e on hydrogenation of samples w i t h d i s l o c a t i o n s a r e shown i n Fig.2. The luminescence spectrum of t h e hydrogenated samples h a s a wide band (H) (Fig.2b) w i t h a maximum of about 0 , 9 5 ev. Nothing d e f i n i t e can be s a i d about t h e s h o r t wavelength s i d e of t h e i n i t i a l

spectrum a s an i n t e n s i v e luminescence band i s l e f t a t t h i s place.

A s t o l o n g wavelength l i n e s , t h e i r i n t e n s i t y i s w e l l seen t o drop sharply.

The temperature dependence of t h e i n t e n s i t y of t h e new luminescence l i n e d i f f e r s s i g n i f i c a n t l y from t h a t of t h e i n i t i a l spectrum l i n e s (Fig.3), t h e maximum p o s i t i o n of t h e new l i n e i s found u n d e f i n i t e . With u s i n g temperatures t h e maximum l i n e v a l u e s h i f t s f i r s t t o t h e

s h o r t wavelength s i d e and then back t o t h e l o n g wavelength s i d e , c o i n c i d i n g w i t h t h e i n i t i a l spectrum l i n e 0,93 ev. The temperature dependence of t h e i n i t i a l spectrum l i n e s i s l i k e l y t o be caused by t h e a c t i o n of a c e r t a i n mechanism of n o n s a d i a t i v e recombination which i s i n i t i a t e d by temperature. The a c t i v a t i o n energy i n t h i s

c a s e is v e r y low and r a n g e s from about 0,003 t o 0,006 ev. A markedly

JOURNAL DE PHYSIQUE

Fig. 2

-

subsequent a n n e a l i n g a t 350°C (b)

,

d i f f e r e n t temperature dependence of t h e l i n e H h a s enabled one t o assume % h a t it d i f f e r s

C from t h e i n i t i a l spectrum l i n e s i n n a t u r e

r

3 /4/. Nevertheless, t h e s t u d i e s i n t o t h e ef-

A f e c t of t h e deformation method (temperature

u

$

s temperature drop i n t h e i n i t i a l spectrum li- n e s 0,93 ev and 0,98 ev have r e v e a l e d g r e a t

A t changes i n t h e a c t i v a t i o n energy of t h i s

E drop. Again, hydrogenation of t h e s a n p l e s i n

r t h e glow d i s c h a r g e h a s demonstrated t h a t i n t h e luminescence spectrum remain i n i t i a l

!i

z of which resembles t h e behaviour of t h e l i n e

r 3 H. Both hydrogenation methods l e a d t o incre-

10 12 14 16 A mu ased quantum luminescence y i e l d t h a t a g r e e s with conclusions i n /lo/ on blocking of non- r a d i a t i v e recombination channels w i t h hydro- gen. Annealing of hydrogenated samples a t t h e temperatures of 600 t o 6500C c a u s e s r e d u c t i o n i n t h e i n i t i a l spectrum except f o r some a n n e a l i n g of t h e short- wavelength spectrum p a r t , Fig. 2 ( c ,d). Thus hydrogenation of def or- med s i l i c o n samples r e s u l t s i n a marked quenching of t h e l o n g wave-

Fig. 3

-

1.8 temperature dependence of t h e l i n e H i n t h e 1.6 i n i t i a l sample, 0

-

med sample; A

-

-

1.4 t h e s h o r t wavelength spectrum s i d e of unhyd-

1.2 rogenated sample.

1.0

ad l e n g t h spectrum p a r t r e l a t e d w i t h t h e r e a r -

0.6 ranged d i s l o c a t i o n s t r u c t u r e . The p o s s i b i l i t y of such an i n f l u e n c e of hydrogen i s confirmed

0.4 by t h e experiments on n e u t r a l i z a t i o n of loca- l i z e d paramagnetic c e n t e r s i n a-Si f o r which

ai? t h e number of introduced hydrogen atoms s M d

0 be much g r e a t e r than t h a t of t h e unpaired s p i n s t h e r e /l1/. The same r a t i o was found on producing hydrogenated germanium /12/.

E v i d e n t l y , i t p o i n t s t o t h e f a c t t h a t i n amorphous m a t e r i a l s e x i s t and may chemically r e a c t w i t h atomic hydrogen o t h e r nonparamag- n e t i c d e f e c t s similar t o p a i r e d d a n g l i n g bonds /13/. The same type of p a i r i n g can a l s o be expected,on r e l a x e d d i s l o c a t i o n s on which no ESR s i g n a l i s found t o occur but l i n e s i n t h e luminescence spectrum a r e observable. The breaking of such bonds w i t h hydrogen could re- s u l t i n quenching of a p p r o p r i a t e luminescence l i n e s .

KNICHTS J.C., BIEGELSEN D.K., SOLONON I., Solid S t a t e Commun.

22

(1977) 505.

DROZDOV N. A,, PATRIN A. A., TKACHEV V.D., P i s 'ma 2h.Eksp.f eor.

P i s . _oss 3 (1976) 651 JETP Leet. 2 (1976) 597

.

ImAN ni. A.

,

u.

,

,

YARYKIN N. A. Zh.Eksp.Teor.Fiz. 82 (1982) 509. Sov-Phys. JETP (2) (19821-294

ZHULIS V.A., OSSIPYAN Yu.A. Zh.Eksp.Teor.Fiz. 58 (1970) 1259.

EREKENXO V.G., NIKITEMCO V.I., YAKDJOV E-B. Zh.Eksp.Teor.Piz.

(1977) 1129.

ERLING L.C,, PATEL J.R. Appl.Phys.Lett., 4 (1979) 73.

1381.

f

V ~ E R F. 0.

,

,

, ²

9. BONDARENKO I.E.9 EFU31ENKO ^V.G.9 NIKITENKO V.I., YAKIDilOV EoB.

Phys.St.Sol.(a) 9 (1980) 341.

10. PANROVE J ; I . , LADPERT M.A., TARNG 1fl.L. Appl.Phys.Lett.,

z,

(1978) 433.

11. E(APLAN D. et al. Appl,Phys.Lett,, 33-(1978) 440.

12, CONNEL G.A.N., PAWLIK J.R., Phys.Rev., B13 (1976) 787.

13. LEE J.H., CORBETT J.M. Phys.Rev., B8 (1973) 2810.