Method and arrangement for treating silicon plates

A method for treating a substrate in a reactor during chemical vapor deposition, for the purpose of depositing substances on the substrate by introducing different gases into the reactor, said method comprising the steps of:

• a. providing a reactor including a microwave cavity formed by cavity-defining walls, the reactor having a gas inlet and a gas outlet communicating with the cavity;
• b. providing a microwave generator and a waveguide adjacent to the reactor for introducing microwaves through a reactor wall into the reactor cavity, wherein the waveguide includes a longitudinal axis;
• c. providing a substrate holder within the reactor cavity, the substrate holder having a longitudinal axis that is substantially coaxially aligned with the waveguide longitudinal axis for supporting a substrate in spaced relationship with the cavity wall, wherein the substrate holder is made from a material that has a low loss factor and includes a substrate supporting surface extending transversely relative to the longitudinal axis of the substrate holder:
• d. placing on the substrate-supporting surface of the substrate holder a substrate onto which substances are to be deposited;
• e. introducing microwave energy into the reactor cavity from the microwave generator to heat the substrate to a desired temperature;
• f. maintaining the temperature of the reactor walls below a vapor deposition temperature;
• g. forming a coating on the heated substrate by introducing gases into the reactor cavity through the gas inlet for deposition of a coating substance onto the heated substrate;
• h. after forming the coating, simultaneous with the introduction of additional microwave energy into the reactor cavity, introducing into the reactor cavity through the gas inlet an etching gas;
• and
• i. maintaining the microwave energy introduced into the reactor at a power level sufficient to produce a plasma from the etching gas to etch a surface of the substrate and to clean the reactor walls of possible impurities.

Apparatus for treating a substrate in a reactor cavity during chemical vapor deposition to deposit substances on the substrate by introducing different gases into the reactor, said apparatus comprising:

• a reactor including a gas inlet and a gas outlet, the reactor defining a microwave cavity;
• a microwave generator and a waveguide positioned adjacent the reactor cavity to introduce microwave radiation into the reactor cavity for heating a substrate positioned within the reactor cavity, the waveguide having a longitudinal axis;
• a substrate holder within the reactor cavity for supporting a substrate, the substrate holder having a longitudinal axis and positioned in substantially coaxial alignment with the longitudinal axis of the waveguide to space the substrate from a wall of the reactor and in a position to receive microwave radiation from the microwave generator;
• means for maintaining the temperature of the reactor walls below a vapor deposition temperature;
• and a closure plate between the waveguide and the reactor cavity for providing a gas-tight shield to prevent flow of gases from the reactor cavity to the microwave generator, wherein the substrate holder is made from a material that has a low loss factor to permit the passage therethrough of microwaves without substantial heating of the substrate holder.