Documents disponibles écrits par cet auteur

Rapid thermal annealing of donor implants in gallium arsenide / Rachid Bensalem 

Public ISBD Titre : Rapid thermal annealing of donor implants in gallium arsenide Type de document : texte imprimé Auteurs : Rachid Bensalem, Auteur ; Brian J. Sealy, Directeur de thèse Editeur : University of Surrey Année de publication : 1986 Importance : 181 f. Présentation : ill. Format : 30 cm. Note générale : Thèse de Doctorat : Microelectronics : Angleterre, University of Surrey : 1986 Bibliogr. f. 182 - 188 . Annexes Langues : Anglais (eng) Mots-clés : Rapid  thermal  annealing n+-surface  layers Selenium-implanted  GaAs van  der  Pauw  measurements Index. décimale : D004086 Résumé : Rapid thermal annealing was used to produce n+ surface layers in tin- and selenium-implanted GaAs. Hall effect and differential Van der Pauw measurements were performed and peak electron carrier concentrations of about 9 x 10¹⁸ cm-³ with corresponding sheet resistivities as low as 28 Ω/□, were achieved for high-dose, room-temperature Sn and Se implants. To realise this, development of new encapsulants and improvements to existing annealing methods were made. A novel method of depositing evaporated AIN for protecting the GaAs surface has been developed. This consists of the evaporation of Al in the presence of pure ammonia gas or an aqueous NH₃/N₂ gas mixture. The evaporated AIN layers were characterised using RBS and RHEED techniques and found to consist mainly of Al, N and O (as contaminant). These layers were used to successfully encapsulate GaAs at temperatures of up to 1100°C which is well above 950°C, the characteristic maximum useful temperature achieved using the existing CVD Si₃N₄. A double-layer encapsulant, consisting of ≈ 300 CVD Si₃N₄ plus 600 evaporated AIN was also developed and found to withstand even higher temperatures (≈1150°C) and to provide more reliable and reproducible results than either AIN or Si₃N₄ when used singly. A double graphite strip heater was developed in order to improve the accuracy of annealing temperature and time measurements. This method was compared to existing annealing methods (single graphite strip, incoherent light and electron beam annealers) and was found superior in terms of temperature accuracy and reproducibility. A simple thermodynamic theory has been developed to explain the incorporation of Sn and Se implanted into GaAs using results obtained from a detailed study of electrical properties measured as a function of annealing temperature and time for 1 x 10¹⁴ cm-² dose implanted at an energy of 300 keV and RT. The electrical activity was found to increase with time and temperature but for sufficiently long times, this activity saturates for a given temperature. Detailed analysis of the data produced: i) an activation energy of 1.2 ± 0.1 eV which is suggested to be that required to remove Sn or Se from a complex defect where it is inactive or compensated and subsequently place it on an appropriate vacancy where it acts as a donor and, ii) activation energies of diffusion of 2.5 ± 0.1 eV and 4.3 ± 0.4 eVfor Sn and Se implants in GaAs, respectively. Rapid thermal annealing of donor implants in gallium arsenide [texte imprimé] / Rachid Bensalem, Auteur ; Brian J. Sealy, Directeur de thèse . - [S.l.] : University of Surrey, 1986 . - 181 f. : ill. ; 30 cm. Thèse de Doctorat : Microelectronics : Angleterre, University of Surrey : 1986 Bibliogr. f. 182 - 188 . Annexes Langues : Anglais (eng) Mots-clés : Rapid  thermal  annealing n+-surface  layers Selenium-implanted  GaAs van  der  Pauw  measurements Index. décimale : D004086 Résumé : Rapid thermal annealing was used to produce n+ surface layers in tin- and selenium-implanted GaAs. Hall effect and differential Van der Pauw measurements were performed and peak electron carrier concentrations of about 9 x 10¹⁸ cm-³ with corresponding sheet resistivities as low as 28 Ω/□, were achieved for high-dose, room-temperature Sn and Se implants. To realise this, development of new encapsulants and improvements to existing annealing methods were made. A novel method of depositing evaporated AIN for protecting the GaAs surface has been developed. This consists of the evaporation of Al in the presence of pure ammonia gas or an aqueous NH₃/N₂ gas mixture. The evaporated AIN layers were characterised using RBS and RHEED techniques and found to consist mainly of Al, N and O (as contaminant). These layers were used to successfully encapsulate GaAs at temperatures of up to 1100°C which is well above 950°C, the characteristic maximum useful temperature achieved using the existing CVD Si₃N₄. A double-layer encapsulant, consisting of ≈ 300 CVD Si₃N₄ plus 600 evaporated AIN was also developed and found to withstand even higher temperatures (≈1150°C) and to provide more reliable and reproducible results than either AIN or Si₃N₄ when used singly. A double graphite strip heater was developed in order to improve the accuracy of annealing temperature and time measurements. This method was compared to existing annealing methods (single graphite strip, incoherent light and electron beam annealers) and was found superior in terms of temperature accuracy and reproducibility. A simple thermodynamic theory has been developed to explain the incorporation of Sn and Se implanted into GaAs using results obtained from a detailed study of electrical properties measured as a function of annealing temperature and time for 1 x 10¹⁴ cm-² dose implanted at an energy of 300 keV and RT. The electrical activity was found to increase with time and temperature but for sufficiently long times, this activity saturates for a given temperature. Detailed analysis of the data produced: i) an activation energy of 1.2 ± 0.1 eV which is suggested to be that required to remove Sn or Se from a complex defect where it is inactive or compensated and subsequently place it on an appropriate vacancy where it acts as a donor and, ii) activation energies of diffusion of 2.5 ± 0.1 eV and 4.3 ± 0.4 eVfor Sn and Se implants in GaAs, respectively.

Exemplaires

Code-barres	Cote	Support	Localisation	Section	Disponibilité	Spécialité	Etat_Exemplaire
D004086	D004086	Papier	Bibliothèque centrale	Thèse de Doctorat	Disponible

Documents numériques

BENSALEM.Rachid.pdf URL