A method of increasing the performance of an FET device by aligning the channel of the FET with the [110] crystal direction of a {100} silicon wafer. The {100} silicon wafer and the image of a lithographic mask are rotated 45 cc.degree. relative to each other so that, instead of the channel being aligned parallel with the [100] crystal direction in the conventional fabrication, the channel is aligned approximately parallel with the [110] crystal direction. The mobility of the carriers is higher in the [110] crystal direction thereby increasing the performance of the FET with only a minor modification in the lithographic process. The novel FET results with its channel aligned approximately parallel with the [110] crystal direction.
Integrated circuits are oriented on a substrate at an angle that is rotated between 0 to 45 degrees from a direction parallel or perpendicular to a preferred crystalline plane direction, such as the cleavage plane, of the substrate. Parameters such as stress and mobility of transistors may be optimized by adjusting the angle of rotation of the substrate. For a rotated substrate CMOS device design, other stress control measures may be used, such as a stress control or tensile liner, over an NMOS transistor, PMOS transistor, or both, to further adjust the stress and improve performance.
P channel transistors are formed in a semiconductor layer that has a (110) surface orientation for enhancing P channel transistor performance, and the N channel transistors are formed in a semiconductor layer that has a (100) surface orientation. To further provide P channel transistor performance enhancement, the direction of their channel lengths is selected based on their channel direction. The narrow width P channel transistors are preferably oriented in the <100> direction. The wide channel width P channel transistors are preferably oriented in the <110> direction.
The present invention provides FinFETs on the same substrate utilizing various crystal planes for FET current channels in order to optimize mobility and/or to reduce mobility. An embodiment of the present invention provides a substrate having a surface oriented on a first crystal plane that enables subsequent crystal planes for channels to be utilized. A first transistor is also provided having a first fin body. The first fin body has a sidewall forming a first channel, the sidewall oriented on a second crystal plane to provide a first carrier mobility. A second transistor is also provided having a second fin body. The second fin body has a sidewall forming a second channel, the sidewall oriented on a third crystal plane to provide a second carrier mobility that is different from the first carrier mobility.
Integrated circuits are oriented on a substrate at an angle that is rotated between 5 to 40 degrees from a direction parallel or perpendicular to a preferred crystalline plane direction, such as the cleavage plane, of the substrate. Parameters such as stress and mobility of transistors may be optimized by adjusting the angle of rotation of the substrate. For a rotated substrate CMOS device design, other stress control measures may be used, such as a stress control or tensile liner, over an NMOS transistor, PMOS transistor, or both, to further adjust the stress and improve performance.
The present invention provides CMOS structures including at least one strained pFET that is located on a rotated semiconductor substrate to improve the device performance. Specifically, the present invention utilizes a Si-containing semiconductor substrate having a (100) crystal orientation in which the substrate is rotated by about 45.degree. such that the CMOS device channels are located along the <100> direction. Strain can be induced upon the CMOS structure including at least a pFET and optionally an nFET, particularly the channels, by forming a stressed liner about the FET, by forming embedded stressed wells in the substrate, or by utilizing a combination of embedded stressed wells and a stressed liner. The present invention also provides methods for fabricating the aforesaid semiconductor structures.
