In order to improve the performance of the a(amorphous)-Si:H/SiC:H superlattice avalanche photodiode (APD), a-Si:H/SiC:H superlattice reach-through APDs (SRAPDs) have been fabricated on ITO(indium tin oxide)/glass substrates by plasma-enhanced chemical vapor deposition (PECVD). For a typical electron-injection SRAPD, the ratio of room-temperature electron and hole impact ionization rates ( alpha / beta ) is 10.2 at an electric field 3.33*10/sup 6/ V/cm, the optical gain is 506 at an applied reverse-bias V/sub R/=18 V and an incident power P/sub in/=5 mu W emitted from a He-Ne laser, the rise time is 1 mu s at a load resistance R/sub L/ 1 k Omega , and the excess noise factor is 6.53 at a multiplication M=48.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>