Comprehensive,in operando, and correlative investigation of defects and their impact on device performance

Abstract

Despite the long history of research that has focused on the role of defects on device performance, the studies have not always been fruitful. A major reason is because these defect studies have typically been conducted in a parallel mode wherein the semiconductor wafer was divided into multiple pieces for separate optical and structural characterization, as well as device fabrication and evaluation. The major limitation of this approach was that either the defect being investigated by structural characterization techniques was not the same defect that was affecting the device performance or else the defect was not characterized under normal device operating conditions. In this review, we describe a more comprehensive approach to defect study, namely a series mode, using an array of spatially-resolved optical, electrical, and structural characterization techniques, all at the individual defect level but applied sequentially on a fabricated device. This novel sequential approach enables definitive answers to key questions, such as: (i) how do individual defects affect device performance? (ii) how does the impact depend on the device operation conditions? (iii) how does the impact vary from one defect to another? Implementation of this different approach is illustrated by the study of individual threading dislocation defects in GaAs solar cells. Additionally, we briefly describe a 3-D Raman thermometry method that can also be used for investigating the roles of defects in high power devices and device failure mechanisms.

Validation of Raman spectroscopy as a tool for mapping transport parameters in inhomogeneous N‐doped 4H‐SiC

“…[3][4][5] A fast screening of such wafers prior to electronic device fabrication, e.g., for identifying structural and doping inhomogeneity, is highly desirable for high-yield device production. 6 Magneto-transport measurements are the established method for in-depth studies of electric transport phenomena in semiconductors. 7,8 Amongst others, measurements of the specific resistivity and the Hall coefficient in low fields yield charge carrier density and mobility when analysed with appropriate microscopic models.…”

Preface to the Special Topic on In-Situ and in-operando Characterization of Semiconductor Materials and Devices

“…Jiang et al dedicate the review to the up-to-date developments in the in-situ/operando optical, scanning probe microscopy, and spectroscopy techniques specifically for organic semiconducting films and devices [1] . Simultaneous probes of film morphological evolution, crystal structures, semiconductor-electrolyte interface properties, and charge carrier dynamics, as revealed by advanced in-situ/operando characterization, effectively facilitate the exploration of the intrinsic structure-property relationship of organic materials and the optimization of organic devices for advanced applications.…”