Characteristics of p-i-n Junctions Produced by Ion-Drift Techniques in Silicon

Abstract

p‐i‐n junctions were fabricated by ion‐drift techniques using lithium in p‐type silicon. Highly compensated intrinsic regions from 0.1 to 5.0 mm were obtained. At temperatures between 120° and 200°C, the space charge of thermally generated carriers in the intrinsic region distorted the lithium ion distribution, producing linear graded junctions whose gradients were between 10¹¹ and 10¹⁴ atoms/cm³/cm. Room‐temperature capacitance measurements were used to determine the impurity distribution. Agreement was found between calculated and measured values of the impurity gradient. Precipitation of lithium ions in the intrinsic region was not observed. The increase of the direct current under reverse junction potential as a function of the increased width of the depletion region permitted measurement of the diffusion and depletion‐region‐generated current components. The value of the diffusion current component at any temperature was proportional to the resistivity of the p‐type silicon. The depletion‐region‐generated component was proportional to the width of the depletion region.