Method for forming a layer on a substrate at low temperatures

A method for forming an oxide layer on a substrate, the method comprising:

• generating a plasma adjacent to at least one surface of the substrate, wherein the plasma is generated via microwaves from a gas or a mixture of gases containing oxygen, wherein the microwaves are coupled into the gas, which is contained in a process chamber, by at least one magnetron via at least one microwave rod arranged opposite to the substrate, the microwave rod comprising an outer conductor and an inner conductor;
• setting the following process conditions:
• mean microwave power density in [W/cm2] to P=0.8-10 W/cm2;
• plasma duration in [s] to t=0.1-600 s;
• process chamber pressure in [Pa] to p=2.67-266.64 Pa (20-2000 mTorr);
• distance between substrate surface and
• microwave rod in [mm] to d=50-120 mm,
• wherein the above and optionally further process conditions are matched to each other such that the substrate is held at a temperature below 200° C. and an oxide growth is induced on the surface of the substrate facing the plasma.

The method of claim 1, wherein the process conditions for an oxide growth of <4.5 nm at a substrate temperature of T<200° C. are set such that the following equation is fulfilled:

• PA·tB·pC·exp(−(d−d0)/λ)<K,
• wherein the parameters of the equation are defined as follows:
• d0 is a distance offset in [mm] in the range of 0-30 mm,
• λ is a characteristic length in [mm] in the range of 30-120 mm,
• A, B and C are choosable coefficients in the range of
• A=0.8-1.5;
• B=0.5-1.3;
• C=−1-−0.3, and
• K is a constant in the range of 11-4.

The method of claim 2, wherein the parameters are in the following ranges:

• d00-10 mm;
• λ=35-80 mm;
• A=1-1.2;
• B=0.8-1;
• C=−0.8-−0.7;
• K=8-4.

The method of claim 2, wherein the parameters have the following values:

• d0=0 mm;
• λ=70 mm;
• A=1.1;
• B=0.9;
• C=−2/3;
• K=4.