Nitride Semiconductors for Ultraviolet Detection
Abstract
GaN and AIN have been deposited on sapphire and SiC using gas-source MBE and extensively investigated via high resolution TEM. Below the critical thickness, AIN only contains threading dislocations emanating from the misfit dislocations; above this thickness, defects parallel to the growth surface greatly increase. The defect density of AIN grown on SiC at 1100 deg C is much lower than that contained in material deposited at 700 deg C. Deposition of GaN on sapphire or SiC results in a larger number of threading dislocations caused by the large misfit as well as a high concentration of dislocations parallel to the growth surface. Both types of defects are decreased in density if the GaN is deposited on AIN. Monocrystalline GaN thin films have also been deposited via layer-by-layer deposition on SiC(0001) substrates from triethylgallium and ammonia. Source concentrations of Ga and exposure times strongly affect the growth process. The near surface region of monocrystalline BP has been converted to BN via exposure to atomic N produced from N2 in an ECR source, as proven by XPS measurements. Current-voltage measurements show an increase in resistance by a factor of 40 after the conversion. Development of (1) ohmic and rectifying contacts, (2) facilities for reactive ion etching and (3) a photo- and cathodoluminescence system are also underway.... Thin films, GaN, AIN, Gas- source MBE, Sapphire, SiC, Threading dislocations, Layer-by-layer deposition, BP, BN, Ohmic and rectifying contacts, Reactive ion etching, Photoluminescence, Cathodoluminescence.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1993
- Accession Number
- ADA267877
Entities
People
- Robert F Davis
Organizations
- North Carolina State University