A novel shallow trench isolation technique

Juing Yi Cheng*, Tan Fu Lei, Tien-Sheng Chao

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


Shallow-trench isolation processes which involve refilling using deposition of oxide and polysilicon were investigated. Our results show that the oxide-filled shallow-trench isolation technology based on chemical-mechanical polishing (CMP) is difficult to control and results in poor uniformity. Use of this technology, also involves in the dishing effect in wide field regions. However, shallow-trench isolation technology using a masking nitride layer, polysilicon refill, the CMP process with high etch selectivity, and local oxidation of polysilicon is easily implemented and absolutely field oxide encroachment. (bird's beak) free. Although the CMP process results in the dishing effect in wide field regions, the local oxidation of polysilicon can reduce the amount of dishing. The polysilicon-filled shallow-trench isolation process can also achieve excellent uniformity across 6-inch diameter silicon wafers due to the high etching selectivity of polysilicon to chemical-vapor-deposited (CVD) oxide and SiN. Moreover, the n+/p junction leakage current of polysilicon-filled shallow trenches is comparable to that of oxide-filled shallow trenches. This simple and easily controllable process is a very promising candidate for shallow trench isolation.

Original languageEnglish
Pages (from-to)1319-1324
Number of pages6
JournalJapanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
Issue number3 SUPPL. B
StatePublished - Mar 1997


  • CMP
  • Dishing
  • Oxide-filled
  • Polysilicon refill
  • Shallow-trench isolation


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