Authors: C-T Sah, B.B. Jie and Z. Chen
Affilation: University of Florida, United States
Pages: 485 - 492
Keywords: interface traps, surface states, MOSFET, MOST, compact model, device physics, history
A review of the electronic or electron and hole traps on silicon surfaces and interfaces is given. They are increasingly affecting the electrical signal properties of silicon diodes and transistors as the technologies for digital, analog and memory applciations advance. In contrast, protonic traps or hydrogen traps affect the reliability and endurance or long-time properties (rather than short-time signal properties) of diodes and transistors, and integrated circuits. This review covers the 60-year history from the first quantitative study on barrier heights on 'bare' silicon surface in the form of Bethe (or Schottky) metal/Si surface barrier diodes in 1946 by Meyerhoff in his physics PhD thesis at the University of Pennsylvania (prior to becoming a Particle Physics Professor at Stanford), to the latest applications of a most sensitive monitoring method (base terminal recombination current) of interface traps for the endurance of memory transistors reported in 2006 by Victor Kuo of Power Semiconductor Corporation of Taiwan. Historical experiments are described which seemed to all point to a broad enegy distribution of the interface traps at the SiO2/Si interface with a U-shaped density of bound quantum states or energy levels, rather than single or few energy levels. This energy distribution of interface traps is not inconsistent with expectation from the extension to the 1950's Slater perturbation theory for bulk ion impurity states to a periodic crystalline potential, which was extended by Sah to purturbations from random distribution of bond length and angle of the Si:Si and Si:O bonds at the SiO2/Si interfaces of state-of-the-art MOS dides and transistors.