Metal layout for radio-frequency switches

A radio-frequency (RF) switching device comprising:

• a first terminal and a second terminal;
• and
• a plurality of field-effect transistors (FETs) arranged in series to form a stack, one end of the stack electrically connected to the first terminal and the other end of the stack electrically connected to the second terminal, each of at least some of the FETs including a source contact and a drain contact, a first group of fingers electrically connected to the source contact, and a second group of fingers electrically connected to the drain contact and arranged in an interleaved configuration with respect to the first group of fingers, at least some of the first group of fingers and the second group of fingers including a first metal M1 and a second metal M2 arranged in a stack, at least one of the first metal M1 and the second metal M2 including a tapered portion to yield a current carrying capacity that varies as a function of location along a direction in which the corresponding finger extends, the second metal M2 further including a portion implemented over and having a width greater than a respective source contact or drain contact.

A radio-frequency (RF) switching module comprising:

• a packaging substrate configured to receive a plurality of components;
• and
• a die mounted on the packaging substrate, the die having a switching circuit including a plurality of field-effect transistors (FETs) connected in series to form a stack, one end of the stack electrically connected to a first terminal of the switching circuit and the other end of the stack electrically connected to a second terminal of the switching circuit, each of at least some of the FETs including a source contact and a drain contact, a first group of fingers electrically connected to the source contact, and a second group of fingers electrically connected to the drain contact and arranged in an interleaved configuration with respect to the first group of fingers, at least some of the first group of fingers and the second group of fingers including a first metal M1 and a second metal M2 arranged in a stack, at least one of the first metal M1 and the second metal M2 including a tapered portion to yield a current carrying capacity that varies as a function of location along a direction in which the corresponding finger extends, the second metal M2 further including a portion implemented over and having a width greater than a respective source contact or drain contact.