Effects of Silicon Misorientation Angle on the Rf and Dc Characteristics of GaAs-on-Si Mesfets

Abstract

ABSTRACTA systematic experimental investigation has been undertaken for the optimization of the wafer parameters and processing for silicon wafers intended for use as substrates for MBE growth, with emphasis on heteroepitaxial growth of GaAs-on- Si. Within this investigation, results are presented of an initial study focused on the optimization of the magnitude of the misorientation angle towards a <110> direction for the growth of GaAs on (001) Si wafers. This angle controls the structure of the stepped (001)Si surface and can influence the defect density and surface smoothness of the GaAs-on-Si layers. Silicon substrates misoriented from 0 deg. up to 9 deg. were cut to specification and subsequently used for the epitaxial growth of GaAs MESFET structures. MESFETs were fabricated and their dc and RF characteristics compared. The resistivity of the GaAs-on-Si buffer layers was evaluated and correlated to the results from device characterization. This work presents the effects of the magnitude of the angle of misorientation in the range from 0 to 9 deg.