SIMS DEPTH PROFILING OF VERTICAL P-CHANNEL SI-MOS TRANSISTOR STRUCTURES

SIMS depth profiling during O-2(+) bombardment has been performed to a nalyse epitaxially grown Si p-n-p layers, which define the p-channel r egion in vertical Si-p MOS transistors, as well as to establish ''on-c hip'' depth profiling of the functional vertical device. The SIMS dete ction limit of P-31 in Si, phosphorus used as n-type dopant in the tra nsistor, has been optimised as a function of the residual gas pressure in the SIMS analysis chamber and of the sputter erosion rate. We demo nstrate that good vacuum during SIMS analysis combined with high erosi on rates allows the simultaneous quantitative SIMS depth profiling of n- and p-type dopant concentrations in the vertical transistor. Small area ''on-chip'' SIMS depth profiling through the layered structure of Al-contact/TiSi2/Si(p-n-p)/Si-substrate has been performed. Factors i nfluencing the depth resolution during ''on-chip'' analysis of the tra nsistor are discussed especially in terms of sputtering induced ripple formation at the erosion crater bottom, which has been imaged with at omic force microscopy.