正电子概况VIII 正电子技术在材料科学 中的应用-半导体 叶邦角 LNSI 核固体物理研究室 Laboratory of Nuclear Solid State Physics, USTC
ℷ⬉ᄤᡔᴃᴤ᭭⾥ᄺ Ёⱘᑨ⫼ -ञᇐԧ 䙺㾦 Ḍԧ⠽⧚ⷨおᅸ L a b o r a t o r y o f N u c l e a r S o l i d S t a t e P h y s i c s , U S T C ℷ⬉ᄤὖމ V I I I
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正©电子在半导体中的应用 e source thermalization OOOO e diffusion typical diffusion length: 入=100nm trapping
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半导体材料 ●第一代半导体材料：Si,Ge ●第二代半导体材料：Ⅱ-V族化合物 (GaAs, InP等) ●ⅡVI族化合物等单晶(CdSe等)， ●子 第三代宽带隙半导体：IV-IV族化合物(SiC等) 单晶、微晶、纳米晶和非晶半导体
ञᇐԧᴤ᭭ ϔҷञᇐԧᴤ᭭: Si, Ge Ѡҷञᇐԧᴤ᭭: III-V ᮣ࣪ড়⠽˄GaAs, InP ㄝ) II-VIᮣ࣪ড়⠽ㄝऩ˄CdSe ㄝ˅ˈ ϝҷᆑᏺ䱭ञᇐԧ: IV-IV ᮣ࣪ড়⠽˄SiC ㄝ) ऩǃᖂǃ㒇㉇䴲ञᇐԧDŽ
Positron Studies of Semiconductor Defects (PSSD) PSSD-2004,第4届，美国华盛顿州立大学 。 PSSD-2002,第3届，日本东北大学 PSSD-1999,第2届，McMaster Univ.加拿大 PSSD-1994,第1届，Halle,.德国
Positron Studies of Semiconductor Defects (PSSD) • PSSD-2004,4ሞ, 㕢ढⲯ乓Ꮂゟᄺ • PSSD-2002,3ሞ, ᮹ᴀϰ࣫ᄺ • PSSD-1999,2ሞ, McMaster Univ. ࡴᣓ • PSSD-1994,1ሞ, Halle, ᖋ
PSSD-Topics 1.Basic work such as identification of defects:defect formation, migration,agglomeration and annealing. 2.Momentum distribution studies of defects:coincidence Doppler broadening,angular correlation of annihilation radiation (ACAR) 3.Low-k/High-k dielectric insulating materials in semiconductor devices 4.Theoretical calculations of momentum distributions and positron lifetimes 5.Slow beam studies of surface and near surface regions of semiconductors 6.High resolution positron lifetime studies of semiconductors 7.Semiconductor defects studied by the experimental methods other than positron annihilation 8.Industrial application of positron annihilation to semiconductor devices
PSSD-Topics 1. Basic work such as identification of defects: defect formation, migration, agglomeration and annealing. 2. Momentum distribution studies of defects: coincidence Doppler broadening, angular correlation of annihilation radiation (ACAR). 3. Low-k/High-k dielectric insulating materials in semiconductor devices 4. Theoretical calculations of momentum distributions and positron lifetimes 5. Slow beam studies of surface and near surface regions of semiconductors 6. High resolution positron lifetime studies of semiconductors 7. Semiconductor defects studied by the experimental methods other than positron annihilation 8. Industrial application of positron annihilation to semiconductor devices
Positron Annihilation in Semiconductors Defect Studies R.Krause-Rehberg H.S.Leipner Springer Series in Solid-State Science,1998
Positron Annihilation in Semiconductors Defect Studies R.Krause-Rehberg H.S.Leipner Springer Series in Solid-State Science, 1998
Introduction Questions of semiconductor industry Defect types? Defect charge states? Defect concentrations? Answers of positron annihilation Vacancy-like defects and defect complexes Size of a vacancy (mono-,di-,vacancy cluster) Neutral or negatively charged vacancy-complexes Positively charged defects are invisible Sensitivity limits 1014-1019 cm-3
I n t r o d u c t i o n
Positron in materials positron wave-function can e+Quelle 11.27 Mev Thermalization be localized in the attractive potential of a defect Diffusion annihilation parameters change in the localized state Y0.511 Mev e.g.positron lifetime Trapping and Annihilation increases in a vacancy 59 lifetime is measured as time difference between 1.27 and 0.51 MeV quanta defect identification and quantification possible
Positron in materials
Positron trapping -Vacancy Perfect lattice [110]direction (001]direction (110]direction Atom potential in GaAs(110)plane Positron wave function in GaAs(110)plane Positrons are repelled by positive atom cores
