In-Situ Pretreatment Approach for Surface Deterioration Alleviation Amidst Thermal Desorption of Si(100)
- PDF / 320,828 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 87 Downloads / 160 Views
J2.3.1
In-Situ Pretreatment Approach for Surface Deterioration Alleviation Amidst Thermal Desorption of Si(100) A.F. Pun1 , X. Wang1 , J.B. Meeks1 , S.M Durbin2 , and J.P. Zheng1 1 Department of Electrical and Computer Engineering, Florida A&M University and Florida State University, Tallahassee, FL, USA 2 Department of Electrical and Computer Engineering, University of Canterbury, Christchurch, NEW ZEALAND ABSTRACT Within this article, a novel in-situ method is proposed as a modification of thermal desorption utilizing pretreatment which can be applied to systems subject to material deposition, substrate heating, and creation of non-oxidizing environments (vacuum or inert atmosphere). Following the theoretical development of this proposed method, involving the fue ling of the oxide-reduction reaction with segregated sacrificial material, the method is demonstrated experimentally on Si (100) wafers utilizing ex-situ atomic force microscopy for resulting surface topography analysis and in-situ reflective high-energy electron diffraction for crystalline information during the modified thermal desorption progression. INTRODUCTION Forgoing to silicon-based device construction, manufacturers typical discard wafer native oxide layers utilizing thermal desorption as the favored means over ion bombardment and chemical etching due to simplicity, usage ease, and minimal contamination. However, as the thermally driven chemical reaction necessary for oxide reduction transpires, the wafer surface rapidly deteriorates requiring the necessity for homoepitaxial growth of micro- meter thick buffer layers to restore surface integrity. This customary procedure is undesirable due to the time and material utilized and furthermore without the assurance of eliminating stacking faults. Thus, it is highly beneficial to develop a method to frustrate the chemical reaction from etching the wafer surface, with such secondary goals as expedient implementation, readily integratable into existing systems, and financially beneficial. THEORY Oxide species present on silicon wafers have been well studied utilizing x-ray photospectroscopy (XPS) [1-3], which has revealed silicon bonding configurations corresponding to 14 oxygen atoms (Si1+, Si2+, Si3+, and Si4+, respectively). Of these four bonding configurations, only Si2+ and Si4+ are stable isolatable species, corresponding to SiO and SiO 2 , respectively, and thus contribute significantly to stoichiometric balance of the native oxide, whereas Si1+ and Si3+ are meta-stable thus being confined to defect sites near the oxide/wafer interface. Further, SiO 2 is believed to be located on the oxide exterior due to the higher availability of oxygen, as compared to SiO confined in the interior region. Past studies of the desorption of SiO and SiO 2 at high temperatures has revealed that SiO is volatile at temperatures subjacent those necessary for silicon dioxide, and will either evaporate due to its lower vapor temperature or auto-oxidize according the following reaction:
J2.3.2
2SiO => Si + SiO 2 ;
(
Data Loading...
