Disordering and anomalous surface erosion of GaN during ion bombardment at elevated temperatures

Kucheyev, S. O.; Williams, James S.; Zou, Jin; Jagadish, Chennupati; Li, G.

doi:10.1063/1.1347010

Cited by 33 publications

(20 citation statements)

References 10 publications

(12 reference statements)

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“…For example, bombardment of GaN with 300 keV Au ions at 550°C has been shown to result in the erosion of an ϳ1000-Å-thick surface layer. 15 Such efficient erosion during elevated-temperature ion bombardment may not only impose significant limitations on the technological applications of ''hot implants'' into GaN but also complicate the interpretation of experimental data, as has been discussed elsewhere. 15,19 The above examples ͑of strong dynamic annealing, somewhat unexpected defect evolution, and ion-beam-induced material dissociation and anomalous surface erosion͒ clearly illustrate the complexity of ion-beam-damage processes in GaN.…”

Section: Introductionmentioning

confidence: 99%

“…15 Such efficient erosion during elevated-temperature ion bombardment may not only impose significant limitations on the technological applications of ''hot implants'' into GaN but also complicate the interpretation of experimental data, as has been discussed elsewhere. 15,19 The above examples ͑of strong dynamic annealing, somewhat unexpected defect evolution, and ion-beam-induced material dissociation and anomalous surface erosion͒ clearly illustrate the complexity of ion-beam-damage processes in GaN. Such an unexpected ͑and certainly interesting͒ behavior imposes significant limitations on the technological applications of ion implantation in the fabrication of GaN-based devices.…”

Section: Introductionmentioning

confidence: 99%

“…Recent ion-implantation studies [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] have revealed that, unlike the situation for mature semiconductors such as Si and GaAs, GaN exhibits a range of intriguing behavior involving extreme property changes under ion bombardment. 19 In particular, it has been shown that dynamic annealing processes ͑i.e., defect-interaction processes͒ in GaN are extremely efficient even during heavy-ion bombardment at liquid-nitrogen temperature.…”

Section: Introductionmentioning

confidence: 99%

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Effect of ion species on the accumulation of ion-beam damage inGaN

et al. 2001

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Wurtzite GaN epilayers bombarded with a wide range of ion species ͑10 keV 1 H, 40 keV 12 C, 50 keV 16 O, 600 keV 28 Si, 130 keV 63 Cu, 200 keV 107 Ag, 300 keV 197 Au, and 500 keV 209 Bi) are studied by a combination of Rutherford backscattering/channeling ͑RBS/C͒ spectrometry and cross-sectional transmission electron microscopy. Results show that strong dynamic annealing processes lead to a complex dependence of the damage-buildup behavior in GaN on ion species. For room-temperature bombardment with different ion species, bulk disorder, as measured by RBS/C, saturates at some level that is below the random level, and amorphization proceeds layer-by-layer from the GaN surface with increasing ion dose. The saturation level of bulk disorder depends on implant conditions and is much higher for light-ion bombardment than for the heavy-ion irradiation regime. In the case of light ions, when ion doses needed to observe significant lattice disorder in GaN are large (տ10 16 cm Ϫ2 ), chemical effects of implanted species dominate. Such implanted atoms appear to stabilize an amorphous phase in GaN and/or to act as effective traps for ion-beam-generated mobile point defects and enhance damage buildup. In particular, the presence of a large conce ntration of carbon in GaN strongly enhances the accumulation of implantation-produced disorder. For heavier ions, where chemical effects of implanted species seem to be negligible, an increase in the density of collision cascades strongly increases the level of implantation-produced lattice disorder in the bulk as well as the rate of layerby-layer amorphization proceeding from the surface. Such an increase in stable damage and the rate of planar amorphization is attributed to ͑i͒ an increase in the defect clustering efficiency with increasing density of ion-beam-generated defects and/or ͑ii͒ a superlinear dependence of ion-beam-generated defects, which survive cascade quenching, on the density of collision cascades. Physical mechanisms responsible for such a superlinear dependence of ion-beam-generated defects on collision cascade density are considered. Mechanisms of surface and bulk amorphization in GaN are also discussed.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of ion species on the accumulation of ion-beam damage inGaN

et al. 2001

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“…However implantation at elevated temperature is reported to imply anomalous surface erosion [20], and the damage is not completely removed, so, a high temperature annealing step is also necessary.…”

Section: Implantation At High Temperature: 500 • Cmentioning

confidence: 99%

Rare Earth Ion Implantation in GaN: Damage Formation and Recovery

et al. 2006

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Rare earth ions implanted GaN has been investigated by transmission electron microscopy versus the fluence, using Er, Eu or Tm ions at 150 keV or 300 keV and at room temperature. Point defect clusters and stacking faults are generated from low fluences (7 × 10 13 at/cm 2 ), their density increases with the fluence up to the formation of a highly disordered layer at the surface. This highly disordered layer is observed from a threshold fluence of 3×10 14 at/cm 2 at 150 keV and 3×10 15 at/cm 2 at 300 keV, and appears to be composed of voids and misoriented nanocrystallites. Its thickness rapidly increases with the fluence, and then saturates. Both basal and prismatic stacking faults were observed. Basal stacking faults are I 1 in majority, but E or I2 have also been identified. I1 basal stacking faults propagate easily through GaN by folding from basal to prismatic planes. Channelling implantation, increasing the implantation temperature from room temperature to 500 • C, or implanting through a 10 nm thick AlN cap reduce the crystallographic damage, particularly by retarding the formation of the highly disordered layer. Implanting through the AlN cap allows the highly disordered layer formation threshold fluence to be increased by one order of magnitude, as well as the annealing at high temperature (1300 • C) which brings about a strong optical activation of the rare earths.

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“…(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23) Both of these phases have Tc values above room temperature (eg. GaMn has Tc's between 450-800 K depending on the amount of Mn in the alloy).…”

Section: Elmentioning

confidence: 99%