Development of an Implant Isolation Process for Heterojunction Bipolar Transistors

Period of Performance: 02/28/1997 - 06/28/1999


Phase 2 SBIR

Recipient Firm

Universal Energy Systems, Inc.
Dayton, OH 45432
Principal Investigator

Research Topics


There is great interest in heterojunction bipolar transistors (HBT) for high-speeed, high-power electronic devices. The major problem in fabrication of HBT circuits is the electrical isolation of individual devices in power device design, where it is desirable to have collector and sub-collector layers 1 um thick or more. Ion implantation can be used to produce mid-gap electron and hole traps which act to compensate for both n and p type materials. In Phase I UES has developed isolation schedules based on MeV energy O+ and B+ implantations. In Phase II, UES proposes to optimize the isolation schedules base on O+ and B+ implantations. The implantation schedules will be optimized with the objective of implementation of the process in the manufactuing of HBTs. Current implant masking scheme utilized thick Au film that adds significantly to the cost. Alternate low cost masking schemes will be developed in Phase II. A pilot production process will be developed by modifying the UES Tandetron acceleratior to accommodate the processing of 4" wafers at high energies and to increase the productivity. These improvements will enable high volume processing of wafers at lower cost to satisfy the future requirements of the Government and Industry.