Graduation Year

2006

Document Type

Thesis

Degree

M.S.E.E.

Degree Granting Department

Electrical Engineering

Major Professor

Stephen E. Saddow, Ph. D.

Keywords

Cubic silicon carbide, Chemical vapor deposition reactor, Control system, Crystal growth, System safety

Abstract

Silicon carbide, SiC, is a semiconductor material which has many diverse uses in many of today's leading technologies. The wide band-gap aspect of the material has been utilized to create power and high frequency electronics, its physical hardness enables its use for MEMS devices, and the biological compatibility make perfect for utilization in medical applications. SiC is not a chemical compound normally found in nature and must be artificially generated. One of the methods used for the creation of single crystal, high quality SiC material is provided through the use of a chemical vapor deposition reactor. The University of South Florida currently has a horizontal hot-wallLPCVD reactor used by Dr. S. E.

Saddow and his group to grow epitaxial SiC material for research grants by ONR and ARL.These agencies have commissioned the construction of a second LPCVD reactor for the primary purpose of growing 3C-SiC, a specific SiC crystal polytype, and this work describes the fabrication of the new reactor, MF2. This reactor was designed using the first reactor, MF1, as a template, but the design was modified to better facilitate single crystalline growth. The environment of the reactor is a very important consideration for crystal growth, and slight variations can cause critical defect incorporation into the crystal lattice. Many conditioning runs were required to facilitate the epitaxial growth of the different polytypes of SiC, and constant switching of the primary hot-zone required for the growth of hexagonal 4H-SiC and 6H-SiC to the hot zone required for 3C-SiC consumed precious resources and time.

The new reactor uses a single primary control to monitor the three most important environmental concerns; hot-zone temperature, gaseous flow, and chamber pressure. The new reactor has been designed to use 100 mm Si substrates instead of the 50mm Si substrate size currently in use by MF1. The construction, testing, and 3C-SiC epitaxial growth on Si substrate capability of a 200 mm 3C-SiC hot-wall LPCVD reactor are demonstrated through this work.

Download

Share

COinS