NU 2014-166
Inventors
Matthew Grayson*
Zhou Wang
Short Description
Novel method for rapidly testing 2D semiconductor quality
Abstract
Northwestern scientists have developed a new method for determining charge density in 2D doped semiconductors. During preparation of doped semiconductor materials charge density gradients can become non-uniform, which negatively impacts device performance and causes process variations. Conventional methods for examining the uniformity of charge densities are cumbersome and expensive. This novel method from Prof. Grayson's laboratory is faster and cheaper because it requires only two measurements of the four-point resistance under varying magnetic fields. In addition, this method can be directly applied to the sample of interest and does not require a large quantity of samples in order to generate a density distribution map. This is a major advantage, as testing multiple samples adds to the cost of the procedure. Thus, this innovative testing methodology has potential to improve testing and calibration of semiconducting materials, which can then impact manufacturing of many types of electronic devices. Figure 1- Density color map of 2-inch GaAs quantum well wafer calibrated by dicing into 4mm x4mm samples and measuring the average density n0 of individual samples. Black arrows represent the locals density gradients calculated from this density map. Green (pink) arrows represent the measured density gradients using corner (flat) contacts of individual square samples. Sample D4 is chosen to demonstrate the invention.
Applications
Advantages
IP Status
Provisional patent application has been filed.