A system for measuring deep-level spatial concentration distributions

A deep-level defect distribution profiling system using both analog and digital data-acquisition concepts is described. Analog circuits and digital data processing are used to provide high-speed acquisition and a high dynamic range, respectively. The implementation has an advantage of easy adaptation with an existing deep-level transient spectroscopy system having minimal software development. Additional advantages are the capabilities of eliminating long-term system drifts and superposition of data taken subsequently for averaging in order to conveniently achieve a desirable signal-to-noise margin. Several examples using ion-implanted n-type and p-type Si Schottky diodes are given. In addition, a metal-oxide-semiconductor field-effect transistor after a Si ⁺ implant and annealing at 600 C is illustrated to indicate a high surface-defect concentration due likely to the recoiling process.