Magnetoresistance Anisotropies in n-Type (001) Si on Sapphire

Abstract

Weak field magentoresistance anisotropies near room temperature were observed on n-type (001) Si on sapphire. They are M_⟨100⟩^⟨001⟩<M_⟨100⟩^⟨010⟩, M_⟨100⟩^⟨100⟩∼0 and M_⟨110⟩^⟨110⟩>M_⟨110⟩^⟨001⟩>M_⟨110⟩^{⟨\bar110⟩}, where the superscript and subscript denote the magnetic field and the electric current directions, respectively. These anisotropies are well explained when it is assumed that the ⟨001⟩ energy ellipsoids make little contribution to conduction, the energy being raised relative to the ⟨100⟩ and ⟨010⟩ ellipsoids due to the large lateral strain induced by the thermal expansion coefficient difference.