LOW-COST PC-BASED SCANNING KELVIN PROBE

We have developed a novel, low cost, scanning Kelvin probe (SKP) syste m that can measure work function (wf) and surface potential (sp) topog raphies to within 1 meV energy resolution. The control and measurement subcomponents are PC based and incorporate a flexible user interface, permitting software control of major parameters and allowing easy use r implementation via automatic setup and scanning procedures. We revie w the mode of operation and design features of the SKP including the d igital oscillator, the compact ambient voice-coil head-stage, and sign al processing techniques. This system offers unique tip-to-sample spac ing control (to within 40 nm) which provides a method of simultaneousl y imaging sample height topographies and is essential to avoid spuriou s or ''apparent'' wf changes due to scanning- induced spacing changes. We illustrate SKP operation in generating high resolution wf/sp profi les of metal interfaces (as a tip characterization procedure) and oper ational electronic devices. The SKP potentially has a very wide range of applications ranging from semiconductor quality control thin film a nd surface analyses to corrosion and biopotential imaging. (C) 1998 Am erican Institute of Physics. [S0034-6748(98)05211-3].