Patent ID: 8316797

Claim:
A microwave plasma assisted reactor comprising: (a) a first microwave chamber having a reference plane at a reference axial location Z 0 , the first microwave chamber comprising an electromagnetic wave source and extending in an axial direction z>Z 0 ; (b) a plasma chamber having an outer wall, the plasma chamber extending into the first microwave chamber such that at least a portion of the plasma chamber is located at z>Z 0 and at least a portion of the plasma chamber is located at z<Z 0 ; (c) a conductive stage for supporting a substrate holder and having a reference surface extending into the plasma chamber and defining a second microwave chamber in the plasma chamber (i) at z<Z 0 and (ii) between the plasma chamber outer wall and the conductive stage; (d) a conducting short adjustably disposed in the second microwave chamber below Z 0 and in electrical contact with the plasma chamber outer wall and the conductive stage, the axial distance between the conducting short and Z 0 being L 2 , and the axial distance between the conducting short and the reference surface of the conductive stage being L 1 ; wherein L 2 and L 1 are capable of adjustment in the reactor by moving the conducting short, such that different microwave modes are produced in the first microwave chamber and in the second microwave chamber during operation of the reactor.