Particulate-free epitaxial process

In a cold purge process for conditioning a gas phase reactor chamber and a wafer therein for deposition of a layer on the wafer using a gas phase deposition process, the reactor chamber including radiant energy lamp means for heating the wafer to effect said deposition, the improvement comprising

• first, communicating at least one gas into the chamber for purging air from the chamber;
• second, communicating a carrier gas into the chamber preparatory to initiation of the gas phase deposition process;
• and
• third, during at least said second gas flow step operating the radiant energy lamp means at a power level below that used for said gas phase processing heating to supply radiant energy at a relatively low intensity level for decreasing the number of particles deposited on the wafer.

An improved predeposition cold purge sequence for preparing a gas phase reactor for gas phase epitaxial growth of a layer on a wafer positioned in the reactor, the reactor chamber system including radiant energy lamp means for effecting said heating for gas phase processing, the improvement comprising:

• orienting the wafer substantially vertically within the reactor;
• passing nitrogen gas through the reactor for the purpose of purging air from the reactor;
• passing hydrogen gas through the reactor for the purpose of purging air from the reactor and stabilizing the hydrogen gas flow through the reactor;
• and throughout said gas flow steps operating the radiant energy lamp means at a power level below that used for said gas phase processing heating to supply relatively low intensity infrared radiant energy to the chamber to substantially eliminate the electrostatic attraction-induced deposition of particles onto the wafer.

An improved low particulate gas phase process for depositing a layer on a wafer within an initially cold reactor chamber at a suitable wafer temperature, comprising

• first, communicating at least one gas into the chamber for purging air from the chamber;
• second, communicating a carrier gas into the chamber preparatory to initiation of the deposition process;
• third, heating the wafer throughout at least said second gas flow step to a temperature between about 180.degree. C. and below said deposition temperature for substantially eliminating electrostatic attraction between the wafer and particulates;
• and
• fourth, heating the wafer to said deposition temperature and supplying reactant gas to said chamber for depositing said layer thereon.

In a gas phase process for depositing a layer on a wafer within an initially cold reactor chamber at a suitable wafer temperature, the reactor chamber system including radiant energy lamp means for effecting said heating for gas phase processing, the improvement comprising

• first, communicating at least one gas into the chamber for purging air from the chamber;
• second, communicating a carrier gas into the chamber preparatory to initiation of the deposition process;
• third, operating the radiant energy lamp means at a power level below that used for said gas phase processing heating to supply radiant energy to the chamber at an intensity level substantially below that required to heat the wafer to said deposition temperature for substantially eliminating electrostatic attraction between the wafer and particulates;
• and
• fourth, heating the wafer to said deposition temperature and supplying reactant gas to said chamber for depositing said layer thereon.