System and method for making Si2H6 and higher silanes

A method for producing a higher silane from a lower silane comprising:

• heating a first lower silane containing stream optionally comprising non-reacting diluents less than 20% by volume of said first lower silane containing stream so that the stream is in a first reaction temperature range while avoiding exposing the stream to a temperature greater than about 20° C. more than the maximum temperature of the first reaction temperature range;
• introducing the heated first lower silane containing stream within the reaction temperature range into a first reaction zone, and
• maintaining the temperature in the first reaction zone in the reaction temperature range, wherein said heating occurs in about 6 seconds or less and the first reaction zone has an average residence time of about 15 seconds to about 60 seconds.

(canceled)

A method of making trisilane from one or more lower silanes comprising:

• mixing a first gas stream comprising silane in a first temperature range and a disilane containing stream having a relatively higher concentration of disilane than the first gas stream to form a second gas stream comprising trisilane, wherein the disilane containing stream is at a lower temperature than the first gas stream and is of a flow rate so the first gas stream is cooled within a third temperature range, wherein the first temperature range is from about 400° C. to about 500° C. and the third temperature range is from about 305° C. to about 375° C. or wherein the first temperature range is from about 425° C. to about 475° C. and the third temperature range is from about 280° C. to about 400° C.