Electronic states at misfit dislocations in partially relaxed InGaAs/GaAs heterostructures

Bandlike and localized states of extended defects in n-type In0.53Ga0.47As

“…Thus, the orientation of the dislocation line at the (001) interface will change as well: 17 (i) under tensile stress, α type yields a misfit dislocation (MD) line in the [1][2][3][4][5][6][7][8][9][10] direction and β type in [110]. (ii) Under compressive stress, α type results in a [110] MD line and β type in [1][2][3][4][5][6][7][8][9][10]. In addition, it is well known that a 60°dislocation is dissociated into a 30°and a 90°Shockley partial dislocation to glide efficiently, as reported in detail by Marée et al 19 Since this movement is energetically unfavorable for the shuffle set of dislocations, 18,20 it is generally believed that mobile 60°dislocations belong to the glide set.…”

“…For sample P_In47 and P_In40, as mentioned in the paragraph on layer strain, the n+ In x Ga 1-x As/substrate interface is under tensile strain and the subsequent lattice-matched is at the p/n− layer. Under this situation, the cross-hatch lines (white dashed lines) located in the [1][2][3][4][5][6][7][8][9][10] direction are thought to correspond with α dislocation MD lines with As (g) core atoms and predominant in both P_In47 and P_In40. Beside α dislocations, sample P_In40 also exhibits a small number of β dislocation MD lines (white dashed lines located in [110] direction) and additional defects called "micro-crack" (dark grooves located in [110] direction), in agreement with literature data for the tensile stressed In 1-x Ga x As/InP system.…”

“…3 However, these methods inevitably lead to extended defects during the heteroepitaxial growth, because of lattice and thermal mismatch. For example, defects lying in the (111) plane cannot be trapped by the shallow trench isolation (STI) sidewalls in the (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11) plane. This is one of the major issues in InGaAs-based devices.…”

“…In the case of dislocations, the effects can be amplified and even modified due to the presence of a one-dimensional (1D) density of states (DOS) along their line direction instead of a single energy level. 4 In past decades, this concept of a 1D DOS, originally introduced to explain the electrical behavior of dislocations in Group IV semiconductors, 5,6 has also been validated in the InGaAs/GaAs system with band-like HD3 states 7 (misfit dislocation) and localized ED1 states 8,9 (α 60°m isfit dislocation). The distinction between a band-like and localized 1D DOS is based on a study of the evolution of the Deep Level Transient Spectroscopy (DLTS) peak on the filling-pulse duration: 5,6,8 for a "localized" 1D DOS, the peak maximum of the DLTS amplitude stays at the same temperature and increases over several decades with the logarithm of the filling pulse duration.…”

Anisotropic misfit strain relaxation in lattice mismatched InGaAs/GaAs heterostructures grown by MOVPE

“…The In x Ga 1Àx As layers were intentionally undoped, but the background net doping concentration with donors indicated by C-V measurements was equal to about 10 16 cm À3 . More details on the characterization of electrical properties of the samples are given in our recent papers [12,13].…”