The Thermal Expansion Coefficient of GaxIn1-xAsyP1−y Epitaxial Layers Grown on InP Substrate

Abstract

The amount of the measured room temperature thermal expansion coefficient of tetragonal strained layers grown lattice matched on the InP substrate used is about 30% greater the expected one for a cubic “relaxed” material. This issue has to be taken into account for the determination of the composition of the quarternary GaxIn1‐xAsyP1‐y layers from both X‐ray and photoluminescence data as well as for the estimation of the thermally created stress field of optoelectronic devices.

Thermal expansion coefficients of ternary AIIIBV solid solutions

“…The third and fourth terms modify the temperature dependence of the TEC somewhat. The thermal expansion coefficient x can be obtained using (5) or (6) by Our calculated TEC obeys the expected tendencies. For a statically compressed lattice we find a somewhat diminished TEC and for a stretched bond length an increased TEC.…”

“…The first term in (6) reproduces the static tension of the lattice. The second term corresponds to the one given in (5), but C2 is corrected by the value yu. The third and fourth terms modify the temperature dependence of the TEC somewhat.…”

“…For example, the amount of the TEC is enhanced by about 30% for thin epitaxial layers which were grown lattice-matched on the substrate. This is caused by the imprinted tetragonal strain of the layer [ 5 ] . By means of EXAFS experiments Mikkelson and Boyce [6] have shown that in Ga,,Inl-,As solid solution the cations are placed nearly a t the positions of a regular f.c.c.…”

The thermal expansion coefficient of AIIIBV multilayer structure

“…in which the stress vanishes in this direction in case of [5,11] gll and E~ represent the relative lattice parameter difference of the strained and the unstrained lattice in and perpendicular to the growth plane. Experimentally the lattice mismatch and 6, is measured with respect to the substrate, For superlattices there are two cases: 1.…”