Hydrogenation of shallow-donor levels in GaAs

Pearton, S. J.; Dautremont‐Smith, W. C.; Chevallier, J.; Tu, C. W.; Cummings, K. D.

doi:10.1063/1.336964

Cited by 172 publications

(27 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2). Such low dissociation energy is close to the dissociation energy of other H-donor complexes [6], of the order of 2 eV. For higher temperature the experimental points deviate substantially from the theoretical curve described by (2).…”

mentioning

confidence: 71%

Passivation of a Bulk Defect E_c-0.22 eV in GaAs by Contact with Phosphoric Acid

Babiński¹,

Goldys²

1991

Acta Phys. Pol. A

View full text Add to dashboard Cite

The Εc-0.22 eV trap in Horizontal Bridgman undoped n-type GaAs may be passivated by contact with phosphoric acid for 8 hours at room temperature. Isochronal annealing, at around 250° C for 1 hour resulted in the partial recovery of this defect. Τhe possible mechanisms of Εc-0.22 eV trap passivation are proposed.PACS numbers: 71.55. Eq, 81.60.Cp, 61.70.At The electronic properties of GaAs depend critically on the localized levels in the forbidden gap. The technological procedures during semiconductor device processing often involve the contact of chemicals like acids or solvents with the semiconductor surface. It has been noticed only recently that these treatments are not as benign as they had been thought and they are capable to change the semiconductor properties [1]. It is our aim to report on the changes of defect concentration in bulk GaAs detected by DLTS (Deep Level Transient Spectroscopy) when GaAs is in contact with phosphoric acid in ambient temperature. We propose that these changes are due to hydrogen diffusion into the near-surface region of the samples. The source of hydrogen is the acid itself.Τhe material examined was undoped (n = 1.5x 10ί 5 cm-3) Horizontal Bridgman GaAs grown in MIT (USA). Two sets of samples were prepared. The samples from the first set were measured and then immersed in 60 % H3PO4 at room temperature for 8 h. Afterwards they were annealed isochronally for 1h between 200° C and 300° C in vacuum (5 x 10' 5 Torr). The samples were heated from room temperature to final annealing temperature in 5 mi. The samples from the second set were subjected to electrolysis in 60 % H3 Ρ O4 at room temperature for 8h. They served as a cathode of electrochemical cell with Pt foil as an anode. Τhe current density was 1 A/cm2 . The DLTS spectrum of as-grown material revealed 4 peaks *This work was supported in part by CPBP 01.05.(277)

show abstract

mentioning

confidence: 71%

Passivation of a Bulk Defect E_c-0.22 eV in GaAs by Contact with Phosphoric Acid

Babiński¹,

Goldys²

1991

Acta Phys. Pol. A

View full text Add to dashboard Cite

show abstract

“…[16][17][18][19][20] Since it is difficult to measure N O and N directly, Eq. where N O Ј and NЈ are the concentrations of unpassivated defects before and after annealing, respectively, which dictate the carrier lifetime.…”

Section: B Understanding and Kinetics Of The Hydrogen-defect Dissocimentioning

confidence: 99%

Minority-carrier lifetime enhancement in edge-defined film-fed grown Si through rapid thermal processing-assisted reduction of hydrogen-defect dissociation

Nakayashiki

Rohatgi

Ostapenko

et al. 2004

Journal of Applied Physics

View full text Add to dashboard Cite

This paper demonstrates that a very short, 1-s, simultaneous firing of screen-printed Al at the back and SiNx antireflection (AR) coating at the front can significantly enhance the minority-carrier lifetime in edge-defined film-fed grown (EFG) ribbon Si via SiNx-induced hydrogen passivation of defects. It was found that 1-s firing in a rapid thermal processing system at an optimum temperature improved the average minority-carrier lifetime from 3to>80μs, resulting in ∼16% efficient 4-cm2 screen-printed EFG Si cells. It is proposed that rapid thermal firing enhances the retention of hydrogen at defect sites by minimizing the hydrogen-defect dissociation. A combination of simulations and experiments reveals that the dissociation of hydrogen is extremely rapid at conventional firing temperatures of ∼700°C. An activation energy of 2.4–2.6eV was determined for the hydrogen-defect dissociation in EFG Si. This activation energy, in conjunction with the room-temperature photoluminescence data, suggests that the impurity-decorated dislocations are the dominant hydrogenation and dehydrogenation sites in the EFG Si. Based on the above understanding, a manufacturable process, involving rapid co-firing of SiNx AR coating, screen-printed Al-doped back surface field (Al-BSF), and screen-printed Ag front grid, was developed in a conventional belt furnace to minimize the degree of dehydrogenation while producing good Al-BSF and ohmic contacts. This process produced 4-cm2 screen-printed EFG Si cells with an efficiency of 15.9%.

show abstract

“…Therefore hydrogenation is carried out either in hydrogen plasma or in atomic hydrogen ͑AH͒. Analysis of the data available in the literature has shown that hydrogenation of GaAs samples in the plasma of an rf discharge at hydrogen pressures p у10-100 Pa [10][11][12] and pϭ0.1 Pa, 13 like in AH flow at p ϭ10 Ϫ2 Pa, 7,14 gives rise to semiconductor structures with similar electrophysical characteristics. This suggests that the penetration of AH into semiconductors depends not as much on the partial pressure of AH as on some other more essential factors.…”

Section: Introductionmentioning

confidence: 97%

Investigation of the penetration of atomic hydrogen from the gas phase into SiO2/GaAs

Kagadei

Nefyodtsev

Proskurovsky

2001

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

View full text Add to dashboard Cite

A comparison experiment has been performed to study the hydrogenation of GaAs samples coated with a thin film of SiO2 (5 nm) and thin-film vanadium samples in a flow of atomic hydrogen produced by a source based on a reflected arc discharge with a hollow cathode and a self-heating electrode. An increase in discharge current I results in an increase in the concentration of atomic hydrogen in the gas phase, NAH, and in a corresponding increase in the atomic hydrogen content (dose), QAH, dissolved in vanadium samples. For GaAs samples, the situation is different. At low discharge currents, an increase in current results in an increase in NAH and in a corresponding increase in QAH. However, beginning from some current I*, further increase in current and in NAH decreases QAH. This suggests that the value of QAH is more dependent on the probability of the penetration of hydrogen atoms into the solid, F, than on NAH. It has been supposed that F decreases substantially as the hydrogen atom energy decreases with increasing discharge current. Another reason for the observed phenomenon may be the formation of a near-surface diffusion barrier of immobile hydrogen molecules occupying interstitials and preventing hydrogen atoms from penetrating the bulk of the sample.

show abstract

Hydrogenation of shallow-donor levels in GaAs

Cited by 172 publications

References 23 publications

Passivation of a Bulk Defect E_c-0.22 eV in GaAs by Contact with Phosphoric Acid

Passivation of a Bulk Defect E_c-0.22 eV in GaAs by Contact with Phosphoric Acid

Minority-carrier lifetime enhancement in edge-defined film-fed grown Si through rapid thermal processing-assisted reduction of hydrogen-defect dissociation

Investigation of the penetration of atomic hydrogen from the gas phase into SiO2/GaAs

Contact Info

Product

Resources

About

Hydrogenation of shallow-donor levels in GaAs

Cited by 172 publications

References 23 publications

Passivation of a Bulk Defect Ec-0.22 eV in GaAs by Contact with Phosphoric Acid

Passivation of a Bulk Defect Ec-0.22 eV in GaAs by Contact with Phosphoric Acid

Minority-carrier lifetime enhancement in edge-defined film-fed grown Si through rapid thermal processing-assisted reduction of hydrogen-defect dissociation

Investigation of the penetration of atomic hydrogen from the gas phase into SiO2/GaAs

Contact Info

Product

Resources

About

Passivation of a Bulk Defect E_c-0.22 eV in GaAs by Contact with Phosphoric Acid

Passivation of a Bulk Defect E_c-0.22 eV in GaAs by Contact with Phosphoric Acid