At&&a Chmca Acta, 272 (1993) 99-103 Elsewer Science Pubhshers B V , Amsterdam 99 Direct determination of trace elements in indium phosphide by atomic absorption spectrometry E Mdella CNRSM, Centro Nazwnak &erca e Svrluppo Mater& VUI G iUarcom 147, 72023 Mesagne, Bnndrsr (Italy) E Sentunentl, G Mazzetto, L Meregalh and M Battagharm Temuv SpA, Centro ficerche Venezta, Vi delk Industne 39,30175 Venezm Port0 Marghera, Vemce (Italy) (Received 25th July 1992) Abstract A method for the atonuc absorption spectrometnc determmatlon of Important unpuntles m mdmm phosphlde (InP) 1s described Results are compared wth those obtained by glow dwharge mass spectrometry To avold accldental contammatlon, no preconcentratlon was used The detectlon hnuts are as low as 10’4-10’6 atoms cme3 Thus method gwes the posslbdlty of checkmg rapidly the amount of lmpuntles m InP polycrystals and dopants m InP single crystals by a relatwely mexpenswe technique Keywor& Atonw absorption spectrometly, Indmm phosphlde, Sermconductors, Trace elements Considerable mterest has been shown recently m III-V semxonductmg materials The substan- tial progress made over the last decade m the preparation and processmg of these matenals, together with the development of highly rehable devxes, has led to great sophlstlcatlon of opto- electromcs technology The properties of mdmm phosphlde (InP), a typical representative together mth galhum arsenide of the III-V semiconductor class, make it of mcreasmg interest m important areas such as optoelectronics, microwave manu- facturmg and high-frequency field effect transls- tors (FETs) InP has a wide energy gap and higher electromc moblhty than semiconductors such as silicon and germanium Temav (Vemce) have developed an mdustrlal prototype process for the production of InP epl- Correspondence to E Mdella, CNRSM, Centro Nazlonale Rlcerca e Svduppo Matenab, wa G Marcom 147, 72023 Mesagne, Bnndw (Italy) taxy-ready substrates The overall process consists of the productlon and charactenzatlon of the raw materials used, the productlon and charactenza- tron of mdnun phosphlde wafers and the recy- clmg of scraps and shmes Indmm phosphlde as a polycrystal 1s obtamed by the very high-pressure synthesis (VHPS) method and the smgle crystal IS then grown by the hquld-encapsulated Czochral- sky (LED) method The steps after growing m- elude onentatlon, cyhndrlcal and surface grmd- mg, cutting of shces and grmdmg of edges The thickness, flatness and surface characterlstlcs of each substate are checked The manufacture of epltaxy-ready product 1s conducted m a class 10 clean room As some well known unpurltles strongly affect the electrlcal features of semlconductors, even at trace levels (Table l), It IS necessary to control accurately the quality both of the mater& being used and of the (mtermedlate) products at each stage of the synthesis Also, the efficiency and 0003~X70/93/$06 00 0 1993 - Elsevler Science Publishers B V All nghts reserved