| abstract |
IC structures, packages and device assemblies with III-N transistors are disclosed herein that include additional materials, referred to herein as "stressor materials", that can be selectively provided over portions of polarization materials to localize the strain in the polarization material to increase or decrease. By providing a compression stressor material, the tensile stress that the polarizing material imposes on the underlying portion of the III-N semiconductor material can be reduced, thereby reducing the two-dimensional electron gas (2DEG) and increasing the threshold voltage of a transistor. On the other hand, providing a tensile stressor material can increase the tensile stress caused by the polarizing material, thereby increasing the 2DEG and lowering the threshold voltage. The provision of suitable stressor materials enables simpler and more precise control of the threshold voltage than if one were only to rely on the recess in the polarization material. |