Patent ID: 8796106

Claim:
A method of making a semiconductor device comprising: forming a filled isolation trench in a semiconductor layer comprising forming a first cavity in the semiconductor layer, and filling the first cavity with insulating material; forming a filled additional isolation trench in the semiconductor layer adjacent the filled isolation trench and separated therefrom by a portion of semiconductor material to be coupled to a reference voltage, the forming comprising forming a first additional cavity in the semiconductor layer, and filling the first additional cavity with insulating material; forming a second cavity in an upper portion of the filled isolation trench, and depositing a material in the second cavity to form a protective cap over the filled isolation trench; forming a second additional cavity in an upper portion of the filled additional isolation trench, and depositing a material in the second additional cavity to form a protective cap over the filled additional isolation trench; and forming protection masks over the protective caps formed in the filled isolation trench and in the filled additional isolation trench, and etching the semiconductor layer.