Faculty Sponsor's Department(s):
IBM’s confined epitaxial lateral overgrowth (CELO) process is a novel device fabrication method that promises a future of laterally grown devices with two-dimensional defect confinements. This unique defect confinement enables monolithic scale integration of very large scale integrated devices and development of both horizontal and laterally devices. The process is being replicated at UCSB for a tunneling field effect transistor; Sputtered SiO2 CELO boxes with a sacrificial layer of Al2O3 collapse after TMAH wet etching. However, a CELO plasma enhanced chemical vapor deposition (PECVD) SiO2 box with an a-Si sacrificial layer does not collapse when etched with XeF2 gas and filled with deionized water (DI). The sputtered SiO2 collapse may be due to film stress rather than capillary force from TMAH wet etch. Consequently, stress of silicon oxide and nitride thin films grown with PECVD using a mixture of high (13.6 MHz) and low (100-450 Hz) frequencies were characterized. Silicon oxide has a compressive stress range between –220 and –360 mega pascal (MPa). Silicon nitride film stress ranges from tensile to compressive, 468 to –127 MPa. Highly compressive, tensile, and zero-stress CELO boxes with a-Si sacrificial layers and XeF2 selective etch will be characterized. Due to metal-organic chemical vapor deposition (MOCVD) selectivity, a SiO2/SiN/SiO2 stack will be used.