High Dose Arsenic Implant for Bipolar Buried Layers

The use of arsenic ion implant for a low sheet resistance and deep junction buried layer process was investigated. Appropriate ion doses and energy were found to obtain the desired buried layer profile using a pre-implant oxide. A low temperature (1050°C) oxidation was employed to remove the highly damaged surface region after diffusion/anneal of the arsenic implant. Damage was characterized after the buried layer process and epitaxial growth. The electrical performances and relative yield of the bipolar devices made from implanted and deposited (solid-source) arsenic buried layer were compared. The results indicated that implanted buried layer produced almost defect free epitaxial layer in the subsequent processing.