LOW TEMPERATURE DEPOSITION OF SixNyHz USING BTBAS AND ALKYLSILANES AND ALKYLDISILANES
Publication Date: 2008-Jun-13
The IP.com Prior Art Database
Described herein are methods and compositions for forming a silicon nitride film at low temperatures.
Background of the Invention
Deposition of silicon nitride dielectric films, such as silicon nitride (Si3N4) and silicon dioxide on semiconductor substrates is an important step in the formation of many FEOL and BEOL integrated circuit (IC) processes. or example, dielectric films may be used to form gates of field effect transistors (FETs), spacers separating adjacent FETs, or sacrificial layers in the DRAM. These films are typically deposited employing a variety of chemical vapor deposition techniques (CVD, ALD, PECVD and PEALD).
Traditionally, silane or dichlorosilane in the presence of ammonia have been used to deposit Si3N4 films at relatively high temperatures (>650º C.) at varying chamber pressures. Another leading silicon nitride precursor is Bis(t-butylamino)silane, (BTBAS), BTBAS is used in the deposition of silicon nitride without formation of ammonium chloride in a low pressure chemical vapor deposition process at >530º C. The deposition process of silicon nitride is carried out in the presence of ammonia in the range of approximately 500to 800º C., and the pressure is in the range of 0.5 to 20 mTorr. Ammonia is introduced separately into the deposition high temperature zone to allow successful deposition. Scaling down of device dimensions, increases in transistor density with increasing integration complexity require deposition of Si3N4 at <500º C.
Invention and Method
1. A new method to deposit SiwCxNyHz thin films and the ability to control the percentage of carbon in silicon nitride in the deposited films at extremely low temperatures (below 530º C.); this is by adjusting the concentration of the reactants in the cocktails or reactant mixtures.
Reactant are a combination of BTBAS with alkylsilanes, dialkylsilanes, polyalkylsilanes, disilanes and polysilane...